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.
"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