First try to run the simple Ubuntu 9.04 OS from the CD and if it's working properly,then its NOT the hardware issue.Its probably something wrong in Windows OS...
Anyway try this:
-Go into the "Safe Mode with Command Prompt" and type the following command:
chkdsk C: /f /r
(Where "C:" is the partition where your Windows OS is installed)...
Now press the ENTER button on your keyboard and the disk checking process will start.If it asks you that it will perform the disk checking process the next time you restart the computer and then you get choice "Y" and "N",type "Y" then press the ENTER button on your keyboard and then type the following command to restart your computer:
Shutdown.exe -s -t 0
Now press the ENTER button on your keyboard and the computer will restart.
-After the computer has restarted,the disk checking process will start.The process may take a VERY long time so let it finish!
-When the process is complete,your computer will restart automatically
Now see if the computer still freezes.If it does,it might be the registry issue too.Download and install the program called "Eusing free registry cleaner" and scan your computer with it and clear ALL the invalid registry that was found!
-Restart your computer...
Try all this and tell us if it helped...
Cheers dude!