I think to give you some help you have to go a little bit mor into detail what action is slow.
First of all i'd recommend that you install the processexplorer of sysinternals on your client to check ram and cpu performance.
Maybe you also try different browsers like Chrome or Firefox.
For your legacy problem with the software that doesn't run thith windows 7 --- did you ever try the XP compatibility mode in windows 7 ? With that one i was even able to install productview 8.0 on windows 7.