Zune Player Software

I have recently purchased a Zune player through Dell.  I have been having problems installing the Zune Software on my Dell Dimension 4600 PC.  During the installation process, it gets to be like 95% complete, and then it slows down and looks like it is trying to do something for about 2 minutes or so.  After that it says the software installation was unsuccessful, and that I should restart my computer and try to install it again.  It isn't any of my security suites blocking it (Mc Afee and Spyware Doctor)  because I turned them both off, and I've even tried re-booting my computer without them starting at start up.  I've tried rolling back my windows media player as well, because I heard about a conflict with windows media player 11 beta version.  I've tried calling Zune and Dell Support only to get hung up on by both lines multiple times.  I have been messing with this since Christmas Eve.  I need help troubleshooting the installation process or I am liable to hold every penny I have for some time.  I'm not saying that I'm necessarily angry at Dell or Microsoft, but this error message is frustrating me.  If you guys at the Dell Support Forums can't help me just like several phone calls didn't help me, then please refer me to someone who can because I need knowledge that I obviously don't have.