Windows 7: Hard drive light stays on and computer freezes randomly in windows 7

I am little bit worried about my harddrive. Previously I had 80 gb harddrive and then I upgraded it to 320 gb. I have dell latitude d630 laptop with two operating system. Windows 7 and XP. When I use Windows 7 then my computer specially hard drive light stays on and mouse is busy and I have to restart my laptop however in my XP this problem is never seen. I also installed vista and deep formatted the hard drive but the problem still persists in windows 7. The system is normal but when I surf internet via mozilla or chrome. This problem arises. I have done everytrouble shooting I can chkdsk and everything but when I use chkdsk in my western digital harddrive, it says error. I am thinking its harddrive issue what do u say?



thanks

OS is Win 7 Prof

Can we get some system spec's?

INTEL DUAL CORE 2.0
INSTALLED RAM 2GB
32 BIT OPERATING SYSTEM
AND i HAVE ALREADY FORMATTED 3 TIMES WITH WIN 7 AND WIN VISTA BUT THE PROBLEM STILL PERSISTS!

Please fill in the system specifications in your profile.