Recently, my friend built me a computer and I thought it was going to be great. I tried installing XP on it the first time, it came up with some errors about how it couldn't find some files. It worked on the other computers so I just installed it anyway and continued. I've tried this with many different XPs and it comes up with the same problem, even though it works on different computers.

Anyway, getting straight to the point, my computer likes to restart by itself occasionally when I start to play a game of Halo PC. That's not the only problem though, each time I restart my computer, a different software installation has an error when I try to start the program up. Sometimes I start up Adobe and it gives me a memory error. Sometimes I start up Windows Live Messenger and it gives me an error about not being able to talk to people.

Most of the things that are happening are pointing to a RAM problem, which is what I thought. I even ran MemTest86 and it came up with a bunch of errors so I got my RAM replaced and the same errors still come up.

I'm starting to think it's either the motherboard or power supply (which is why I'm posting it here). Everytime I try to plug in a USB cord or headphones or microphones into the front, my computer restarts.

This has been happening for a while now and it is affecting my online business. I hope you guys can help me.

It sounds like you diagnosed your own problem. You replaced the RAM, now re-install Windows. Your problems should go away.

What are your system specs, and power supply?

My system specs are as follows:

Asus M2N-E Motherboard
250GB WD Hard Drive
1GB RAM
Asus EAX1300PRO Video Card
18x LG DVD Burner
Generic 510 Watt PSU

I've done what I said but it hasn't fixed the problem. I'm starting to think it isn't the RAM but the motherboard or PSU.

OK, I wasn't clear on whether you re-installed XP after the RAM or not. But since you did, I'd say that you need to look at the DVD ROM for complete connections at the motherboard and the drive. If that's OK then try another drive. I believe that your problem is that the drive is not reading the install CD well. You may need a new drive.

eh, if you have another PSU around swap that in instead if possible, after all it's generic so it's not to be the most trusted..

I don't think it's the CD Drive though. I still get the same errors from MemTest86 even though I've replaced the RAM. I will take your advice and try to re-connect it though.

If memtest is still giving errors then I agree with Vel. Try another power supply. The voltages on that one may be off enough to cause problems with the memory as well as other parts. You can check this in BIOS to be sure they are correct.

Now it's giving me weird times on my computer. Every time I restart, my computer's time is off of the real time. I'm going to check out the PSU.

Replace the CMOS battery. That'll fix that problem.