Contact Sharp tech support? We mostly answer computer-related questions here. Are you trying to use the TV as a computer monitor? Does it work as a TV but fail when you select the the input from the computer? More detail would be most useful.

I had an obscure problem like that under Windows 7 - Couldn't select the TV (a vizio) as output for the PC because the PC didn't detect it with DVI. Couldn't set the TV to DVI input because I couldn't get a DVI signal out of the PC until it detected the TV....