Yesterday morning when I tried to turn on my computer I got the blue screen with the error that unfortunately I did not wrote down for future references.

So, I run the Dell utility and gave me the following error: 

SATA DISK S/N = WD-WCANK2858425 - Read Test
No additional sense information
Test Results: Fail
Error Code: 650F:0240
Msg: Block 362681464: Address mark not found or media

Then I used the Windows XP disk to repair the installation of windows XP and it send me directly to the C drive prompt when I tried to repair the windows installation. I did not want to loose all my files.
 
From the C prompt I call the directories but nothing appear, so from there I run the command CHKDSK and gave me more or less the same error as the utility did.

Then I run the command BOOTCFG /Rebuild but it did not let me to do anything because the same error.

Finally I run the command FIXBOOT and the only option available was to create a new boot sector.

That allowed me to open Windows and I had been able to work with practically no problems.

But...............

Internet explorer 7.0 is acting strange, because some pages are not opened, giving me the 550 error, but from that error page when I click BACK it goes to the right page I was trying to open originally. It does not happen with all pages just with some of them and not always with the same.

I had not turned off the computer because I am afraid it will do the same thing as before.

My question is:

Is this a hardware problem? or a software corruption?

I have many programs installed and the computer is not old, is not brand new either ( 2 years old)

Would be wise to make a System restore to a date previous from yesterday?

Any help will be highly appreciated.