Copy your files to a backup drive, buy a new one for the computer and install Windows on that, copy your files back. You'd want to save your My Documents, Favorites and Desktop folders at least.
If you have messages about drive errors, you do not want to mess around with the drive any more than you need to in order to copy the files out and replace it. Trying to limp along with a failing drive is just asking for a full failure when you least expect it, you need to do a backup NOW while the drive is still usable.
Run PSA Diagnostics(As soon as you press the power key start pressing F12 and select diagnostics)
Incase you get no error then debug the hard drive and delete all the partitions and reinstall fresh copy of windows
If you want to know how to debug give me ur mail id i will forward the file.