Are you saying that when you reset the system that you can see the Replay screens (please wait, one moment please, and the swirl screen)? Then it goes blank when you try to go into some other screen display?
If it is blank all the time I would double check the video cable. If you are using S-Video, make sure it is plugged in properly at both ends. If you are using composite, make sure the yellow connector is plugged in well at both ends. If everything is plugged in well, then try using the video cable with something else to see if it works or swap the video cable with a known good video cable...
If it goes blank after displaying the normal startup screens, then maybe the hard drive has become corrupted. Can you get into the setup screen (the Menu button)? You might want to test your hard drive to see if it has become corrupted. You can use RTVPatch to backup the source drive and at least have it read the system partition to make sure all the sectors are readable. And, you can use extract_rtv5's -v option to verify the file system...
Henry