Reformat the hard drive and reinstall Microsoft Windows on a freshly formatted disk. If your system is sufficiently compromised to have a key logger, then I would take no chances whatsoever.
In fact, I would purchase a new hard drive, install windows on that, reset all your passwords on everything, and then go from there. You can put the old computers hard drive in a USB hard drive caddy, and copy your files off it one by one, making sure you have a good virus scanner set to maximum running when you do it. Additionally, if this was a business computer, I would also use a Linux machine and OpenOffice to access the data. That way, there is no danger of one of the existing files reinfecting the newly created Windows box, and restarting this mess.
If you have a keylogger, then someone has really compromised your system and you have to treat all your old data files as suspect. Assume your passwords have all been compromised. Don't trust any virus scanner ran from inside the affected windows installation.
Where did the keylogger come from? Did it come from a USB key, Web Surfing, or an email?
