I know only how to rescue your precious data(i have similar problem once)
Boot computer from any live CD or better(i use this) from http://falconfour.com/projects.php?pid=7
Once start screen of FalconFour's Ultimate Boot CD
is loaded, select MiniLinux.
Mount your HD, select Midnight Coomander from file Manager menu and copy your data on external disk.
If this is possible on your comp now.
Problem is only how to download and burn FalconFour's Ultimate Boot CD since your comp is unusable now.
Ask friend, use any other Live CD...?