Yea.. it seems that my .net 3.5 is messed up.
I am on Win 7 64bit home premium. I did have an issue a few months back after a registry clean up program removed more that it should have. Didn't notice it right away though. The only program that is affected is Thumbgen. I tried everyting that I could find on the internet with no luck. The net 3.5 folders are there, it is enabled in the Turn Windows Features on and off setup, There are registry entries for net 3.5, but thumbgen won't run... it did work fine before the "clean up".
I am using my old laptop to work with thumbgen now, but it is realllll slow.
The only sure solution is probably and full reinstall fo windows, but for the one occasional program.. I am just not that confident that I want to tackle that. ANY possibility of getting Thumbgen updated to .net 4?

I have no idea of what that entails, but I bet it is more than you want to do, and I completely understand that.
So.. back to the laptop.
Thanks for the replies.
Bob