Since the day I put my computer together (shortly after Thanksgiving '08) it has never done gone to sleep and woke up like it should every time. I would put it to sleep, shake the mouse to wake it up and I had a 50/50 chance of it not waking. Instead, the power supply and fans would spin up, consuming roughly 35w when it normally consumes 170w. This happened with Win XP Pro and now Win 7 HP.

Next problem. If I turn on the vacuum in the same room as my computer, it "shuts it down", but not fully. The screen shuts off and it basically powers down, but the fans still spin and it again, consumes 35w. No other electronics in the same room are effected and voltage sag is negligible.

3rd problem that just started happening the other day. Whenever my AC kicks on, it "shuts it down" (consuming the 35w). My computer remained on, constantly from April 9th to June 8th. I know this because my torrent program had uploaded over 340GB and I took a screen shot at 300GB During that time, for nearly all of May, my AC was on, but never effected it till June 8th when the computer shut down 3 times due to the AC kicking on. No other electronics are effected and voltage sag is negligible.

So, do you think this could be my mobo (Asus M3A78-t)
Or my Power supply (Enermax 625w PRO82+)?

Are you running everything through a UPS?

could be your power supply. Reasoning behind this is simple, PC power supplies are regulated, meaning they should supply a constant 5v 12v etc. They are designed to hold these voltages even when you have some fluctuations in Voltage. So first to rule out outlet, plug pc into another outlet that is not on the same breaker. if problem stops then you can assume there is something going on with the outlet(as a note some devices, such as AC's, Motor's or any high Wattage device; even some low, can make the lines "noisy" or even cause strange voltages, and floating voltages) So rule this out first.
second, if your pc is still shnowing issues, than you may have a crappy powersupply. I should point out that many 40-80 dollar power supplies are rubish, noisy and not very good at holding voltages. I would suspect this is your problem. Also as stated above a UPS is a must for any puter.

Questions to answer.

Yes, everything is hooked up to an UPS. http://www.newegg.com/Product/Product.a ... 6842102048

The not waking from sleep mode has happened at two different houses.

The vacuum on the same circuit (20A) causes the computer to freak. On a different circuit, the computer is fine, but is still effected by the AC which just started happening after a month of having the AC on. And the AC is certainly on a different circuit.

The Enermax PSU was over $100, but I caught it on sale. It does good keeping the 3, 5, and 12v lines at their respective voltages.

I was hoping it wasn't the PSU, because the only way I can really test it is to pull it and put it in another computer that works fine. Pulling the PSU requires me removing the mobo, which means everything else comes out. And I spent like 2 hrs getting everything hooked up and routing wires.

Hmm, with the UPS there I don't think the issue is with the house electrical. Definitely seems like it would either be the PSU or the mobo. Both of which will be annoying to diagnose. I know exactly how you feel about having to tear apart the wiring in a case. It took me a long time to get everything placed and click-tied where I wanted it.

By chance is the PSU modular? If so, do you think you can snag a couple of extra cables/harnesses on the cheap? Personally, I'd rather spend $20 on cables than take the time to pull the wires and then rewire later.

No, the Enermax PRO82+ is not modular, but the Enermax Modu82+ is. If I have to get a new PSU, I am getting a modular one! Trying to route all the excess wires is worth the extra couple dollars for a modular PSU over a conventional one.

With the UPS, I have my receiver and plasma plugged into it (battery backup side) and neither is effected by anything in the house. Having the PSU also plugged into the UPS, I still can't figure out why plugging the vacuum into the same circuit effects it but not anything else. Same with the AC kicking on. I then have an LCD and DVD player plugged into the UPS (non-battery backup side) and they're not effected either.

hum, once again it's pointing to powersupply or mb.
one question, do you hook up your monitor to ups? the reason im asking is anything, and i mean anything that is connected to your pc that requires power, ie monitor, printers, scanners etc can also cause issues, and be another point of issue. basically have you added any new hardware(externial) since this problem started? Some devices are are very noisy, or cause floating voltages.
The reason im focusing on this is simple.

Your computer goes haywire when the ac goes on. SO in a nuttshell you are getting transcient noise/voltages that are causing this issue. Dont rule out anything, from router(if you are not doing wifi), cable modem, monitors etc, all these devices should be protected, and on a UPs. chances are (like most people) their pc is on a ups, and perhaps their monitor, but everthing else is not. and what most people forget is that as long as there is a wire connected to your pc you can have a problem.
example, you have your ups/puter hooked up and it supplies a clean constant 120VAC. now say you have your modem/router connected in another room to another outlet/breaker. Now lets say the modem is on a line that has 122VAC, and noisy. what can happen is because your PC is connected via a wire to your router you have a 2v difference, pluss any noise on that line(this is called a floating voltage.

I would suggest disconnect everything from your pc except your pc, and monitor, (even your internet) so you only have 2 power cables, ie one for pc, one for monitor(all going to ups), then turn ac on and see what happens. if all is good, then slowely add other hardware on and see what causes the problem.

I know im being a bit anal about this, but I have seen floating Voltages wreak havock, and it's something many people are not aware of>(Im a Design engineer btw)

Ok, things on an UPS: Plasma, receiver, computer.
Things not on an UPS: LCD monitor, modem, router. (all on the same circuit)

Problem (not waking from sleep) has persisted before having the plasma or an UPS. Problem has slowly gotten worse even though I have not changed hardware.

I tried to turn my computer on for the first time in a few days with the AC off and no other power things that have caused issues in the past and it took about 10 tries to get into windows. 6-7 times, I never could get the BIOS to even pop up. I finally made it into windows and the computer spontaneously shut down after about 2-3 minutes.

Ok, I put my PSU into another older computer that I have and it's running great. Goes to sleep and wakes up, stays on when the AC kicks on.

The not waking from sleep makes me think it's mobo related and now that I know my PSU works great when put in another computer (and plugged in to the same plug in (UPS) with the same power cord in case anyone is wondering) makes me think it's still mobo related, but I'm not 100% sure. The bad news is I don't have another mobo sitting around to try. I still have over 1 year left on my ASUS warranty.

Computer will not even POST. It just cycles, restarting every, roughly, 1 second. That mobo is done and I still have two 1TB drives in a RAID 0. I'm hopefully going to find a used board on ebay just to get the data pulled off onto a 2TB drive I just bought.

Precisely why I never striped a storage array. I've run numerous operating systems on striped arrays, but never storage drives. Good luck finding a used mobo to pull the data off. And hopefully you'll find one cheap.