Friend of mine has completed major upgrade to his pc. Asrock NF6G Mobo, AMD 64x2 cpu,1 Gb DDR2 Ram, 500W PSU, Hitachi 250Gb SATA HDD. Computer boots and displays CPU details, then Memory...ok, then details Primary/Sec IDE devices and finally the Sata HDD details, then.....nothing! Just sits there...no error messages and no beep codes.I have tried it with bare minimum, ie Mobo, psu, memory & monitor and still the same. Any ideas much appreciated. Thanks.

it appears that post is not running....

remove the CPU, and restart the computer- it with speakers attached (and monitor). If it gives NO ERROR (either beep/ on monitor/ or a Numerical code on the front of the box)- then POST IS NOT RUNNING

The POST IS running. :)
Or at least it was and is when there is a display on the monitor and certain information is displayed on-screen by the POST.

Here are some typical steps completed during Startup...
I think your POST is managing to complete step 8...
--------------------------------------------------------------------------
A typical and successful startup sequence
1. Start of Boot Troubleshooting Walkthrough
http://www.pcguide.com/ts/x/boot/walk/index.htm
2. Yes: The system power supply is functioning
http://www.pcguide.com/ts/x/boot/walk/power1.htm
------------------------------------------------------
You should hear a single short beep at about this point indicating the successful running/completion of the POST.
Some PC’s beep much later, possibly as late as just before step 12.
------------------------------------------------------
3. Yes: Something is being written to the screen during boot up [This may be only a flashing cursor]
http://www.pcguide.com/ts/x/boot/walk/video1.htm
4. The video BIOS message is displayed on the screen for a few seconds and then clears from the screen, or more messages display under it
http://www.pcguide.com/ts/x/boot/walk/vbios1.htm
5. Yes: The system BIOS startup screen is appearing
http://www.pcguide.com/ts/x/boot/walk/bios1.htm
6. The memory test completes successfully
http://www.pcguide.com/ts/x/boot/walk/ram1.htm
7. The BIOS accesses the floppy drives and the boot continues
http://www.pcguide.com/ts/x/boot/walk/seek1.htm
8. The system is able to autodetect IDE devices successfully
http://www.pcguide.com/ts/x/boot/walk/auto1.htm
9. The system is not Plug and Play compatible, has no Plug and Play devices, or has PnP devices but identifies them properly
http://www.pcguide.com/ts/x/boot/walk/pnp1.htm
10. Boot sequence is A: before C: (floppy disk first)
http://www.pcguide.com/ts/x/boot/walk/seqAC.htm
11. The floppy disk makes a noise and the light comes on
http://www.pcguide.com/ts/x/boot/walk/fd1.htm
12. The floppy disk light goes off and the hard disk light comes on as it starts booting
http://www.pcguide.com/ts/x/boot/walk/fd1hdd.htm
13. The hard disk boot process will continue here, if you want to follow it.
http://www.pcguide.com/ts/x/boot/walk/hd1.htm
14. The system continues booting from the hard disk and the message "Starting MS-DOS" or "Starting Windows" is displayed
http://www.pcguide.com/ts/x/boot/walk/hd1os.htm
15. Operating System Loaded From Hard Disk. The system has found a boot sector on the hard disk and is now starting the load of the operating system. The hard disk is working. You have successfully completed the hardware part of the boot process. Any problems encountered after this point should be diagnosed by looking for a more specific problem with a component, or under the section that contains run-time error messages.
--------------------------------------------------------------------------

Your POST appears to complete step 8 above OK.
It may be having trouble with step 9.
Or else trouble with step 13 because it cannot find a bootable drive.
Which step do you think is the last completed successfully?

Check this out...
http://www.pcguide.com/ts/x/boot/walk/auto1.htm
Then this...
http://www.pcguide.com/ts/x/boot/walk/pnp0.htm

Perhaps you need to go into your PC's BIOS Setup and check on the PnP/PCI Configuration?
Setting might be...
Resources Controlled By : Auto
PnP OS Installed : No
If you decide to "Force Update the ESCD" by forcing the BIOS to re-detect all the presently connected PCI hardware, and make new non-conflicting hardware resource allocations, then record those in the ESCD...
You need to set...
Reset Configuration Data : Enabled
...And "Save & Exit Setup".
The BIOS will afterward automatically reset...
Reset Configuration Data : Disabled to lock the new settings [that match the hardware detected].

wow..

well... apparently i am wrong (which i am always happy to be- you learn new things by being wrong...)

Thanks for that very comphrehesive reply. Of course, you are quite correct...the post is starting. It follows exactly as you said and the last display to appear is the correct detection of both the IDE and SATA devices and then it halts. At this stage the Num lock led is on at the keyboard but no input is possible i.e F1 to enter setup. I have stripped it to barebones...Mobo, PSU, and CPU and I hear the warning beeps (no ram present). After installing the RAM there are no beeps in the sequence, just halts at step 8. When fully assembled with all drives present (although none have an operating system as yet) surely I would recieve the 'Non system disk or disk error' message?
Following on from your sequence at step 9, with no pnp devices present and only a cdrom drive hooked up as master on the ide channel (no floppy present) surely I should then get the above mentioned message?? This is a difficult one because I have no access to substitute components i.e Mobo, Ram or cpu (all of which are new...and therefore unproven!) Would greatly appreciate your thoughts. Many thanks.

1. "apparently i am wrong"
Join the club. :)
Been there, done that.
Like they say; the person who never made a mistake never made anything.

2. "At this stage the Numlock led is on at the keyboard but no input is possible i.e F1 to enter setup."
Which suggests a problem with the keyboard. [Which is a PCI device]
At that point in Startup->POST you should be able to hit the appropriate key [F1?] and enter Setup.
How about trying a different [functional?] keyboard?
Unless there's a conflict of resources allocated to the [PCI] keyboard and some other [PCI] hardware item?
My own keyboard is [the only device] using IRQ 01.
In my own Phoenix BIOS [typical?], the attempt to initialize and test the keyboard controller comes fairly early in the POST sequence steps.
I could post the steps of a generic Phoenix BIOS's POST if you'd like to see them, but it's rather long. :(
I wonder if later in the POST there could be a conflict [and POST HALT] when a 2nd device attempts to operate using the same IRQ as the keyboard?
The solution may lie in analysing the POST steps to try to spot the likely cause of a POST HALT.

3. "surely I would receive the 'Non system disk or disk error' message?"
Only if the POST reached the advanced stage of the BIOS attempting to load an OS off some disk/drive.
Is the BIOS configured to boot off IDE or SCSI [SATA]?

4. "with no pnp devices present"
Even if you disconnected all PCI cards, there would probably still be lots of [PCI] PnP devices present [Programmable Interrupt Controller, COM ports, DMA Controller, LPT Port, Numeric Data Processor, Interrupt Controller, clock, speaker, timer, IDE Controller, USB Controller].

5. "surely I should then get the above mentioned message?"
Again...
Only if the POST reached the advanced stage of the BIOS attempting to load an OS off some disk/drive.

Thanks for your reply. The keyboard issue turns out to be a bit of a red herring. It is obviously working early on in the sequence as I am able to enter setup at the appropriate point. I have double checked with an alternative keyboard however. I have tried every possible configuration and the result is always the same. I should add that the AMIBIOS does generate a code at the final screen....001A. I am really unsure what this means but browsing through the codes on the website 00 seems to suggest that control is being passed to INT19 and 1A points to cache ram????? To recap then, The processor is correctly identified as is the RAM. The system autodetects the IDE and SATA devices and again, correctly identifies them.I am able to enter the setup screens at the appropriate time. All of this information is on the display along with the code 001A when the system halts. At this point the keyboard displays the Numlock led and no furthur input is possible (although at this point in the sequence I dont suppose it would be possible anyway). I would, based on this information, greatly appreciate opinions on which component is likely to be faulty i.e Mobo, Ram or CPU. My friend is considering purchasing a replacement Mobo, believing that since the POST sequence reaches the point it does, then the Memory and CPU must be ok. I am really not sure and I feel loathe to offer advice. Once again, many thanks.

You can enter the BIOS setup?

If so, try resetting it to defaults...

If you can't reset the defaults, then remove battery/set the jumper to reset (move the jumper, pull the battery, with the machine unplugged hit the power button and then wait a few minutes...put in a fresh battery and reset the jumper to the 'run' position). Then try with minimal hardware...

Also, in the BIOS setup, disable any not used items...like on board anything that will have an add-in card for (sound, video, network, etc).

It is kind of sounding like you have some kind of resource conflict...

Thanks MJC....I have actually already tried the steps you suggest and I am using minimal hardware i.e Mobo, cpu & Ram. The Mobo incorporates VGA, Audio etc so no external cards fitted. The post does not reach the search for bootable drives. Really frustrating this one....if only I had the necessary components to substitute!

Check out these codes (http://www.dmp.com.tw/tech/dmp-hw/bios/Vortex86_POST_Checkpoint_Codes.pdf).

Find...
00h = Clear data area which only used during Post before execute boot procedure.
And...
1Ah = The memory refresh line is toggling. Checking the 15 second on/off time
next.

So, could this be pointing to faulty ram perhaps?............

Sorry, Sylvander, forgot to comment on your earlier reply (question) The post process only reaches step 8. Never, at any point, does the floppy drive attempt a search or display any led activity.

"Never, at any point, does the floppy drive attempt a search or display any led activity"
So the PC does have a connected and previously functioning FDD?
Do you know [could you check] whether the BIOS Setup includes configuration settings for the FDD, like...
Boot Up Floppy Seek : Enabled
With this set you should hear the FDD giving a brrrp-brrrrp as it is checked, provided the POST were to get that far. As you have mentioned, the fact that this isn't happening suggests that step [11] isn't reached.

There might be other settings of interest, like...
Boot Sequence : a,CD-ROM,C
Quick Power On Self Test : Disabled

PnP/PCI Configuration
Resources Controlled By : Auto

"So, could this be pointing to faulty ram perhaps?"
Wish I knew. :(
What I'm wondering is...
Those codes = 00 and 1A...
Are they displayed because they were the last steps completed, or are they notification that those steps failed?

Well, I have managed to get the system to boot but I think it is a 'sticking plaster fix'. I checked out all options in the Bios again and noticed an entry for AM2 Boost. This is an Asrock utility for improving Memory/chipset performance by 12%. In Bios defaults this is disabled. I enabled it and straightaway the POST completed and the drives were accessed. I installed Vista on the new SATA drive and all appears to be ok.....at the moment! Should I now be suspecting the integrity of the DDR2 Module I wonder? Is it adviseable to populate 2 banks rather than just 1 when using DDR2? Your thoughts would be appreciated!

1. "Should I now be suspecting the integrity of the DDR2 Module I wonder?"
I don't see why you'd suspect it.
You've discovered by chance the correct BIOS configuration setting to make things work.
Would be a good idea to learn more about this "AM2 Boost" feature, and why it needs to be enabled to make things work.
Find AM2 HERE (http://www.asrock.com/mb/overview.asp?Model=ALiveNF6G-DVI&s=AM2).
And see Hybrid Booster (http://www.asrock.com/mb/HybridBooster.html).

2. "Is it advisable to populate 2 banks rather than just 1 when using DDR2?"
I'm no expert on this; can't think why you would use one arrangement rather than another.
Doesn't your manual explain the RAM arrangements that will work?
The [rather good] manual on my old PC has 3 pages on permitted memory configurations.

Sounds like the board may have been O/C'd with the Hybrid Booster allowing protection and thus the boot to complete.

However, to perform overclocking is at risk of hardware damage and boot failure. With two safety features, "ASRock U-COP" and "Boot Failure Guard", Hybrid Booster will minimize the risk of overclocking.

Thing is though, this is a brand new Mobo. As stated, it will not boot with default Bios settings but will if the AM2 boost is enabled, but this is an optional overclocking feature and therefore should not be needed for a normal successful POST and Boot???

Doing a little research...

AM2 Boost is a memory timings/frequency optimizer. So with that in mind it is very possible that in the default config your RAM and the preset memory timings were not working out well. With Am2 Boost enabled, the proper timings/frequencies for your installed RAM are now set/utilized.

If it is working with it enabled, then that is the way it needs to be set to actually work with your installed RAM. ( I suppose you could manually tweak the RAM settings to get favorable results, too.)

Thankyou all very much for your help and advice with this issue. The system does seem stable so hopefully its a success! I think one thing has been proved beyond doubt...when troubleshooting you have to keep an open mind!
Best wishes.

My mind is so open I sometimes think I can hear the wind whistling through it. :D

Now make a note on paper of your friends' PC's BIOS Setup [configuration] settings [all of them].

Is the OS working OK with the new hardware?

If all's well with the software...
Make image backups of all his partitions.
Ideally save to an external USB 2.0 HDD.