Windows 7 and webpage not loading

Hello,

Have 5 new Windows 7 computer all work fine except for one webpage that we use almost every day. The webpage works fine with Windows XP and never has an issue, however all 5 Windows 7 have issues. I can sometimes clear Temp internet files and it may work for a few minutes then back to showing disconnected.
Tried other browsers on Windows 7 all have the same issue.
What am I missing in Windows 7?
I even installed virtual XP mode and it work 1 time then it stopped.
I'm at a loss.

Thanks for any help,