from my favorite disk imaging program support website, a very helpful guide to fixing disk read or write errors due to glitchy items like bad IDE cables: http://www.terabyteunlimited.com/kb/article.php?id=152
This problem can be caused by overclocking, overheating, a hardware problem, or a BIOS or firmware bug or configuration issue.
To determine if the mainboard, memory, or CPU is at fault:
If the memory diagnostic does not report any errors, check the following:
Start a Command Prompt and then run chkdsk x: /f where x: is the drive to check.
For example: chkdsk c: /f
Note: If running Windows Vista or Windows 7, you must run chkdsk from an Administrator Command Prompt.
If none of the above helps, the problem may be due to weak sectors on the drive surface. If the issue you are having involves a hard drive, download and run the hard drive manufacturer’s diagnostic utility or a third-party utility designed to scan and repair hard disk surfaces. Below are links to some major hard drive manufacturer’s home pages:
If you still have not narrowed down the problem, try adjusting the system BIOS parameters below, for the drive(s) with which you are experiencing the problem. These settings, if available, are typically found under “Integrated Peripherals” or in the “Drive Configuration” section.
When there is no root password for a live session in linux you can type:
sudo passwd root
Then enter a new unix password
Another way: in Debian there is no root user only type
#sudo su -
If you need root access in Ubuntu then it’s different, there is no actual root, with Ubuntu you need to do sudo, this line shows you how.