I had an optical wireless mouse with keyboard on my old system and tried using it on the new one, but started using the one they sent me with computer to see if that was the problem. Ordered new wireless optical mouse with keyboard thats compatible with system. Also I got an external cd burner, because I didn't think about it when I ordered the computer, to back some things up but ended up taking it back . Ordered one from dell thats for my system. Maybe the other one caused some kind of problem.. Who knows..