Pop in your Windows OS Disk and choose Add/Remove Windows Components. Then uncheck the Internet Explorer. When its done, uninstalling IE, reboot then do the same but only this time, make sure you check mark IE to reinstall it. Your good to go from there, if the problem dosent resolve after then I would suggest you drink some caffeen and search then net for the same thing I just posted here. But then again thats just a simple solution that I know has to work. Or....
maybe I just need some caffeen myself.

There's a utility which fixes or reinstalls internet explorer and checks windows system files for integrety.. here's a link for the explanation and download of IEFIX.

http://windowsxp.mvps.org/IEFIX.htm