Glenn,
1)If there is a memory card inside the camera, please take it out and check.
(OR)
2)As u told the Problem occurred after downloading pictures to pc , it might be infected with VIRUS so please FORMAT the camera.(TO FORMAT The camera goto settings of the camera)
3)If still the same issue , check by changing the settings to default.(It could say RESET or FACTORY SETTINGS)
Ricky
February 2010