iTunes update mobile device error
Each time I have tried to update iTunes on my PC, I keep getting the same error message at the end: "Service 'Apple Mobile Device' (Apple Mobile Device) failed to start. Verify that you have sufficient privileges to start system services." If I ignore the message, I can't open iTunes at all; it says it wasn't installed correctly. If I have it try again, I just keep getting the same message. I've tried restarting my computer as well as uninstalling and reinstalling iTunes, both several times, but with the same result. What's going on? What am I missing? Please help.
Thanks!
Windows 7