Windows 7: No signal detected in WMC for no apparent reason

I have had my current PC for over a year, running Windows 7 with Media Center, and for almost the whole time I have had my OTA antenna hooked up to my PC and have never had issues. Today I decided to clean out the dust inside my computer, so I unplugged everything, including the coaxial cable from the antenna. After I was done, I plugged everything back in, and now I cannot get a signal. The antenna cable is screwed in firmly into the tuner card. Any ideas on what's going on?

Maybe its your TV tuner card that is not firmly placed.

I have had issues with my TV tuner as well and what I did was unplug it, wipe it a bit if its dusty then plug it again more firmly in place and after that, it would work just fine again. But in your case, it says, its the signal that's being problematic.

You can also rerun your TV setup perhaps and see if that helps. Its somewhere down the Tasks section in Windows Media Center.

It seems that if the card was not connected quite enough it would not even show up in my device manager. It's there all right, and there's no indicators that there is anything wrong with it. I ran the signal detection task in WMC but it still can't find a signal.

I had the same thing happen to me when I stopped the search for a signal during setup, I fixed it by uninstalling and reinstalling the drivers, hopefully this could work for you