OK, I didnt read the question toooo closely - you can connect. If the common denominator is IE as the only working browser then I would agree with SD - check your connection settings.
First off, you shouldn't need four browsers?? Assuming you can work with one, let's say Firefox, since it's the probably the most popular after Ie, then click on on tools>options>advanced then click on connection & come back & tell us what you see.
