You are absolutely correct that it makes a difference between x32 and x64. Thankfully, Windows 7 is smart enough to know the difference and will not install 64bit drivers on a 32bit system. However, it will install 32bit drivers on a 64bit system (this is for compatibility reasons). So it is very possible that the folks doing the upgrade may not have installed the proper graphics driver. I would also check your network card driver as a bad driver there could also lead to the unusual behavior you are seeing.
Brian
"My father was very sure about certain matters pertaining to the universe. To him, all good things - trout as well as eternal salvation - come by grace and grace comes by art and art does not come easy." Norman Maclean, A River Runs Through It