PC wont start

[jakkusto]

heres the deal. this afternoon i shut down my pc, and everythign shut off like normal. However, after it shut off, i heard a high pitch sound comgin from the computer (like a high frequency, electric sound). I couldn't figure out why it was making this noise, so i went to the power supply in the back and flipped off the power switch. I came back a couple hours later, and after i turned the power supply back on, i tried to start up by hitting the power button on the front...but nothing happened. However, it's still making that high pitch sound while the power supply in the back is turned on (big black switch with O and - is in the on position). Also, if i turn off this switch, after a few seconds, the diode on the front panel of the computer lights up faintly for a few seconds and then goes out. As i said, hitting the "power on" button on the front has no effect whatsoever on the PC...I havnt noticed any other problems with my pc lately, and its still under a year old...i suspect power supply is to blame, but im gonna borrow a friend's and see if i can get the comp to work. In the meantime, any suggestions would be greatly appreciated.

MSI K89 Neo-4 F mobo
Antec 400 watt PSU
AMD Athlon 64 3400+

if you need other specs let me know

[mjc]

Yeah, I'd say the power supply is the most likely culprit...

How high pitched? It is possible that the sound you are hearing is the power supply's fan.

[jakkusto]

It's up there, its sort of like the sound you hear when a TV is left on...barely audible but definatly there. I actually came back to my room after i sent that last post and let the computer sit with the PSU on for a few minutes and tried to hit the switch on the front, and it actauly worked again, as im writing this from the actual computer, but id be stupid to think it was just a fluke. Iv also had problems with this particular model of PSU before; the one i have now was a replacement for a dud that i recieved when i first built this pc. Iv also had problems with my low-power standy mode lately (the one where almost the entire computer turns off except for the RAM) - instead of going to standy, it just shuts all the way down. The higher power standy mode still works fine. I'm not sure if thats a PSU issue or a BIOS issue, but i thought id throw that out there as its the only other problem iv had with the computer recently. thanks for the feeback

[jakkusto]

The PSU exhaust fan is supposed to only turn on if needed, and i didnt feel any air coming out the back before when i heard that sound, however its possible that it could be an internal fan that i cant see. But again, its a really high pitch sound and doesnt sound like air is being displaced

[mjc]

Fans that seize up tend to emit high pitched squeals...

[Sylvander]

See A malfunctioning SMPS may generate high-pitched sounds, since they do in fact generate acoustic noise at the oscillator frequency. (http://en.wikipedia.org/wiki/Switched-mode_power_supply)

"Find" it there.

[mjc]

After this past weekend...I'm even more inclined to name the power supply as your problem. Mine is now doing the same thing...high pitched noise. The fan gave a horrible squeal Friday and stopped, now when it gets hot it gives off a very high pitched noise (Sat. and Sun. it ran without noise, then last night it started getting noisy)...

Put in the RMA for it a few minutes ago...it will be here by the end of the week.