hey im having the same problem with my labtec media wireless desktop 800. i thought maybe it was the fact that for some reason 2 keys at the same time wouldn't work but ctrl commands like ctrl+a for select all work fine. i also thought it might be the computer cause im using it with a laptop running ubuntu but it doesn't work on a desktop running xp either. batteries are new and the mouse [its a combo] that uses the same reciever works fine.