I'm having troubles with my 3.2GHz Mac Pro, and having trouble figuring out what is going on. It will randomly restart for no reason, and is effectively useless at the moment. The thing is nothing ever happens consistently. It doesn't restart after a specific amount of time. Sometimes the front LED will flash after it restarts, most of the time it does not. When it does flash, an LED inside might light up on a RAM slider, or both, or even on the motherboard itself, but that's never consistent either. Sometimes nothing lights up. A fan even revved up pretty loudly one time, which was unnerving to say the least. I ran the (quick) Apple Hardware Test and it didn't find anything wrong. I couldn't run the extended test because, surprise, the Mac restarted on me. My biggest suspicion is the PSU might be bad. Some of my PC buddies have also suggested replacing a BIOS battery, but since it's a Mac, that might be different or not even the case. If there is a better way to test more of the hardware, such as the PSU I'm suspicious about, that would be nice to know. If it definitely is the PSU, advice on how to replace it and what to replace it with would be great. Would I just any old PSU (with the right/better wattage), or a special Apple-approved PSU?