Which version of Internet Explorer (IE) are you using? If you are using a 64-bit Vista, try using the 32 bit IE and see if that works.
Here's the path to 32 bit IE:
"C:\Program Files (x86)\Internet Explorer\iexplore.exe"
Also, open IE with no add-ons and see if it work fine. If they do, one of the add on's may be corrupted.