What happen?

[Black]

i have a GA-81PE1000-Pro G mobo.there is problem with this mobo,last year my psu burn in,when i open the psu,there is small black spot on the psu pcb.after i replace the psu,i turn on the my pc,all fan are working,but there are not display in the screen.there is no beep sound when i turn on the pc.and than, i remove the ram,there is a beep sound that detect no ram installed,and than i installed back the ram,boot up again,and no dislay again.before this i was upgrade the bios to f5 version, and there is no problem at all,the system run stable.but after the psu burn,there mobo came to this problem

[odannyboy000]

Sounds like your video card. Do you have onboard?

[Black]

no,my mobo does not have integrate video card.but my video card is ok

[Paul Komski]

but my video card is okHow do you know. Does that mean that it works in another system?

Are you now getting a POST beep?

[rond36]

It sounds to me like when your PSU burnt out it burned the motherboard out too.

[Sylvander]

1. "i remove the ram,there is a beep sound that detect no ram installed"
That's good; it means the POST is running, testing, and warning, of the failure of the 1st RAM test

2. "then i installed back the ram, boot up again, and no display again"
(a) This suggests the POST is still running and testing, but some test [B]that comes after the 1st RAM test in the POST sequence, is failing [designed to give no beep code] and causing the HALT of the POST at that point.
This is normally [but not necessarily always] a failure to initialise the video.
I echo Paul; HOW DO YOU KNOW YOUR VIDEO CARD IS OK?
(b) Another possible cause is that the RAM is partially faulty...
And the BIOS is configured to SHADOW the video BIOS to a location in RAM, and that location is faulty, so the video BIOS fails to work normally, the video cannot be initialised, and the POST halts with no beeps.
This might be fixed by resetting the BIOS defaults...
Provided the default configurations include that the video BIOS is NOT shadowed to RAM.

[Black]

yes the vga card can work at other mobo

[Black]

how to reset the bios?i was remove the cmos battery,but the condition is still same.

[Paul Komski]

Detaching all power to the PC and then removing the CMOS battery for say 10 min will usually reset the CMOS settings. On some boards this can be done with a jumper.

Given your history I would agree with rond36 and say your mobo (possibly your CPU or RAM) is shot and the only definitive tests would be to replace them with new parts or try all the main components from another board.

[Black]

how to do the definitive tests ?

[Paul Komski]

how to do the definitive tests
Replace or swap the part(s) with known working ones.

Usually the biggest conundrum is whether the CPU has blown or the Mobo itself (or indeed both of them). Most other peripherals are relatively easy to swap with parts on another box. One can always bite the bullet and purchase the same or an equivalent board and hope it will work with the same peripherals - starting off bare bones and building up. Not nice if the board is an expensive one but should help one to hone down on the problem hardware most quickly.