Computer Freezes During Logon

(Happened about 1 week back)

My computer was working perfectly without any problems last night. When I shut it down at night, and started it back up in the morning. It was working normally until I tryed logging into my account. That's when it just froze (or was going extremely slow). I waited for at least 20 minutes to let in login but it didn't. I restarted my computer later on and in this attempt, the computer got into the desktop, then froze.

I have very important files on my computer which i can't bare to loose. I tried booting the computer in safe mode, but it would still freeze then.

I tried running a new installation with my XP proffesional CD, but it would give me an error that a file is missing, then stop the installation.

My computer is a Dell dimension 2400:

80 Gigabyte HD
768 mb RAM
Pentium 4, 2.8 GHz

Can this possibly be a virus? I think so because just a day before, my clock on the computer had automatically changed the time (which is a sign of a virus). This has never happened before.

I would really appreciate it if someone can help me out here.

Thanks.

-Saad

 

Any help?

 

Can you test your HDD on a different comp to see if it works?

 

I'll check...