Shuts off at XP screen...

Hi-
I built my computer about 3 years ago, and over the years I have upgraded most of it. About a year ago, I bought a new Western Digital HDD to complinent my current 80 gig WD HDD. However, ever since then, it takes me about 3-4 tries to trun my computer on: it gets to the Windows XP screen and then just shuts off.

What can be causing this? I figured it's probably the new HDD, so I reformatted everything to start all over again. I reinstalled Windows, did all of that, but it's still happening. I even unplugged that HDD and tried booting, but it still shut off. Another reason that I think that it may be my HDD is because when I first installed it it was shutting down the computer, but I put one of those little plastic things on the pins (sorry, the exact name escapes me) to slow the speed and it worked. I found out later, however, that I shouldn't have done that, so I took it off.

I was doing some reasearch online and a lot of threads said that it could be the PSU, but I don't feel that it is: this is my second PSU and I bought a pretty good one (at least review-wise) compared to my first. Of course, there's always the possibilty that it is the PSU.

Any help would be appreciated. It may also help to know that I have never overclocked anything. Here are my specs:

AMD Athlon 64 X2 6000+ 3 GHz
GIGABYTE AM2 Motherboard (GA-M55SLI-S4)
2 GB Patriot Memory
eVga Nvidia GeForce 8800GTS KO
Creative X-Fi Xtreme Gamer Sound Card
80 GB Western Digital Caviar HDD
320 GB Western Digital Caviar HDD 300 MB/s
Coarsair HX520W PSU (CMPSU-520HX)

Please help!

if drives are IDE, make sure the "cap" on each HDD is set to "cable select." There is usually a tiny writing on the HDD that shows what the different placement position of the "cap" will do - for example" Master, Slave, CS for CABLE SELECT. Cable select means that the role of the drive (master or slave) is automatically determined by the position on the cable - at the END of the CABLE is the MASTER. Its most likely that this is matter of your computer trying to boot from the wrong drive.

Therefore check the position of the "cap" on each drive.

Easy troubleshooting procedure" remove the new drive and attempt to boot!

******** also************

Also reinstall your RAM!

Good Hunting
Paul

Have you run Memtest86+ to check for RAM errors? Faulty RAM can cause all sorts of weird issues.