I have an Advent PC with a Radeon 6700HD running Windows 7. My monitor is an LED TV, 24" Bush. I plugged an HDMI to DVI cable from TV to PC and it worked fine. I decided to change to an HDMI to HDMI and got no picture. I switched back to the HDMI to DVI and...no picture(tried all sources on tv). I have tried updating, then uninstalling Catalyst, no joy, I have tinkered with settings, no joy. It WAS working, so I know it can but why not now? Please help!