Try a repair install, and sfc
From and administrators account type cmd
in CMD type sfc /scannow.
Repair Install
You can call the company and probalby for S & H, you can get a new CD.
There is software to find lost key numbers. Here is one, but keep in mind I have never used such software and cannot specifically recommend any specific one.
number/ http://pcsupport.about.com/od/produc...pkeyfinder.htm
If you insist on doing a reinstall, do an upgrade. Not suggested, but it will save your programs.
You will not get much better results with an upgrade than you would from the repair install.