What are the problems that CHKDSK reported ?
If you've bad sectors or a failing drive, you could be in trouble.
Try putting your Windows CD in and booting from it. Let it detect your hardware then ignore the options you first get to Repair and so on. Hit F8 to agree to the licensing, then follow the prompt to install Windows.
You then get an options to repair your existing Windows installation when it highlights Windows on your partition. Run the repair utility from that point. many people choose the very first option to Repair and it is not anywhere near as easy from that point. Running the repair from this point will reinstall Windows and preseve your personal data files and programs.
If there were specific CHKDSK errors then it might help to post them in here and one of us will be able to advise further.