Are you sure the resolution and frequency are matched to your tv's specs? It sounds like your pc is putting out a signal that is outside it range. The tv may be downconverting the image so that you can still view it, but the signal is still out of range.
Being that your tv has HDMI, I'm assuming it's a HDTV. Is your tv 720 or 1080? Those will correspond to 1280x720 or 1920x1080. Go to control panel/display settings to change the resolution or right-click an empty spot on the desktop and select properties. Then go to the settings tab.
Under advanced settings you may find options just for the tv.
Glad you figured it out and got it working. Just so we don't go out and buy one of these cheap cables, can you tell us what brand it was? I usually get my cables from monoprice.com and have never had a bad one yet.