Windows booting problem

[IamLost]

I am a Windows user and just recently my Windows was infected I presume by a virus that is stopping my Windows from getting past the booting stage. I have a Knoppix 3.9 live CD, I think there called, which I am using. Wondering if anyone knew a place where I could possibly download a free Knoppix compatible virus scan and protection program. So I can switch back to windows. If so, or if any other suggestions on what the problem may be and how I can fix it please post.

[IamLost]

I searched the forums trying to find an answer to my problem and found this;

"I wonder if it helps you to know that Windows-xp has a repair function. If you run setup and press the right choices you can let Windows install itself in repair modus. I had to do this once before and it went very well, I got everything back. - Of course I don't want to give you any guarantee here because each case might be different, but even for a new installation, I would not expect Windows to overwrite application data - unless you choose re-format or re-partition."

This is what I want to do, but when I enter my Windows Setup I have no idea which category has the repair function. If anyone knows the exact name of what I should click on please post.