Web connection only available via Firefox

This is my first post here and I was directed by a google.com search. A while back (couple months ago) I tried to upload a file to mediafire.com and was given an io error. Thinking nothing of it I uploaded the file from my home pc. I recently tried to do it again to get the same error. I decided I would try another file hosting site and that gave me the same results. I decided to try IE, IE is unable to find a connection at all and it's diagnostic function thinks my router is the problem... clearly this is not the answer. After consideration I recall that every time I start winamp the update screen fails to load because it is unable to find a connection. I use windows XP SP3 and am connected to a network of 3 other computers which are all connected to the same router. The other computers have no problem uploading to the web or getting connections through programs other than Firefox so this is clearly a local issue. Please help me solve my issues.

 

To add information as per the suggestion of the previous post, let it be noted that all of the computes on the network are running versions of Windows XP SP3. The versions may not be identical because all updates are done at each station. (Each computer is a stand alone that has it's own hardware, storage, and operating system)

Hopefully this helps.