Are you working Online or Offline in the File menu of IE? That could make a difference. If you are working online, try the following:
Try specifying a different DNS server on that machine. DNS servers often take some time to update their listings. If your computer is using a secondary DNS server, it probably is getting its info from a primary DNS server that gets updated, and then it SHOULD send those updates out to any secondary DNS servers that rely on it for DNS records (you'll have to forgive me if I got some terminology wrong, it's been a while).
FTP into your web space and make sure you only have one file named index.xxxx or default.xxxx, where you would replace the x's with some sort of HTML, PHP, ASP, or JSP file extension.
Since going to http://www.yoursite.com/ doesn't specify the exact file name, the web server will return an index file of some sort (Linux, and Microsoft NT servers) or a default file (Microsoft NT servers, mostly when they have ASP installed). With multiple index and default files in a given directory, the web server will return the file according to some sort of heirarchy set up in the web server settings.
For example, a directory with the files index.htm and index.html in them will have the index.htm file grabbed if someone requests the directory name and no file name to go with it.