Computer turns on but it doesn't boot up

I was able to successfully install XP home, but when I restarted, it says that I need to start in safe mode because there was an error in the hardware.

MSI K9A-GM2-FIH (MOBO), AMD X2 4000+ 2.1GHz (CPU), Lite-OnLH-20A 1P-186 BK (DVD-Burner),Western Digital WD 7K 8M WD1600AAJS (HDD),CoolMax CX-300 300W (PSU),OZC OZC2P8001GK R(Memory)

You mean your OS doesn't load properly, not it doesn't boot.

That being said, what happened after you restarted in safe mode? Did it work? Did it restart again? Did your computer explode? Did the Pope bless your machine and draw out the demons?

I'd call the Pop back and tell him to do a proper job.

Seriously though, there's obviously something wrong. First thing I'd check is all your connectioins and contacts. Make sure everything is seated and has its connector(s) firmly seated. Check everything here, it might be something stupid. Next I'd try booting it up with a single stick of RAM, and then switching to the other (and also switching slots after that) to see if it's something easier to fix.

I did reinstall XP Home again and now I am getting a message that says that explorer needs to close. I then get a message that says that the DrWatson Postmorten Debuger has a problem and needs to close. What is that exactly?

(When the message that says that explorer needs to close is up, i can do everything fine except go to "My Computer".)

(The debugger in windows shows these two files as problems:

1. C:\DOCUME`1\Owner\LOCALS`1\Temp\WER5fa6.dir00\explorer.exe.mdmp
2. C:\DOCUME`1\Owner\LOCALS`1\Temp\WER5fa6.dir00\appcompat.txt