Boot windows into "Safe Mode" by hitting the F8 key over and over as it boots. That should give you the ability to pull your critical files of the computer to a USB drive.

If it won't boot into safe mode then it's pretty hosed. Download Ubuntu and burn it to a CD with another computer. Boot the computer using the Ubuntu disk using the "try" option. This will let you access your files and move them to a USB drive.

You can continue down the road of trying to fix it but as a IT professional it takes more time to fix than to reinstall. You can always try your local PC place but your looking at $100 a hour shop time. It's my experience that once the registry is been "fixed" they never work right again. <img src="/forums/images/graemlins/frown.gif" alt="" /> Thats why I recommend the reinstall. <img src="/forums/images/graemlins/cheers.gif" alt="" />