Taking a Screenshot

This problem just recently came up. When Im ready to take a shot I usually hit PrntScrn and paste it into photoshop. But today, when I hit paste, nothing came up...

I tried doing alt+prntscrn (the active window gets shot) and it works, it pastes in PS.

Im using Nvidia GeForce 7600GT

#487249

Ctrl+PrntScr?

#487250