WTF did my PSU torch? o_O

[LancerZero]

Oy. Okay - we just made a 1300 mile move. We took along two computers - my homebuilt one, and my mom's, which might as well be homebuilt from all the parts I've replaced for her. We reached our destination, unloaded the comps, and plugged them in. Mine worked beautifully. Hers didn't.

First, what they were exposed to: we also had cats in the two cars, so the air conditioning was never turned off until we pulled into the hotel for the night. We ate our meals standing next to our cars, with the engines running and the A/C on cold. The day before we left, they were exposed to some heat from sitting in the warm cars whilst the movers loaded the truck, but we covered them with blankets (they'd been cold, having not been running for several hours) and cracked the windows to help keep the temp down.

Now, the symptoms. Here's what my mom's comp - an eMachines - did when you pressed the "on" button:

1. The CPU fan and the case fan turned like they were supposed to.
2. The PSU fans did not spin at all.
3. The system did not POST - no beep, no floppy, CD, or HDD activity that I could hear at all.
4. The PSU made a very, very high-pitched sound. It was so high-pitched that I could barely hear it - and my 52 year old father couldn't. My 7 year old nephew could, though, so I know I'm not crazy! XD It is not supposed to make this sound. What's even weirder is that when I turn the PSU off (it has its own power switch), the sound continues for a few second, then increases in pitch and makes a sort of "staticy" sound before cutting out completely.

Finally, the specs:

350 watt Antec SmartPower PSU
FoxConn motherboard
1.66 GHz AMD Sempron CPU
1x 512MB RAM
128 MB ATI Radeon graphics card (AGP)
DVD-ROM drive
Uhh, a sorta generic CD-RW drive.

And that's it. The PSU is the exact same one that my computer has in it, except my comp is just fine.

So, I bought a replacement PSU. It's the same one: 350W Antec SmartPower. But this time, not much happens. I turn on the PSU, then press the computer's "on" button, and the case fan and CPU fan twitch. Not even a full rotation. They just twitch, and then nothing.

I have no idea what to do next. Is it most likely the motherboard? Or is it worse, might it have torched nearly every component in there?

 

[Nubius]

Hmm don't know, but I'm about to make a 1100 mile move in about 4 days so thanks for making me paranoid

Just check your cables and all that good stuff. Might not hurt to remove the ide and power cables then replug them all back in.

 

[turtile]

Only the inner fan spins on that PSU when its not that hot. The back fan only turns on when it gets really hot.

The high pitched noise is common with this PSU and usually they work fine (but its really annoying).

 

[LancerZero]

I checked all the cables, and they're all secure. Tried the IDE cables, as well. Do you have any other suggestions?

 

[FlashDude]

Motherboard is more than likely toast. Reset the cmos/remove the battery. Still nothing? Unhook/Remove everything from the board except power cables (ram, hdd cables, video card, soundcard/any other add on cards) and try restarting again still no post/beeps then take the board out of the case and place it against a solid surface and hit it with the biggest hammer you can find! Alot of people think that when this happen's it's the PSU but about 99% of the time its the board. Oh btw emachines are famous for this.