My expert analysis brings me to think that you have a bad cable-video thing. My advice to you, go on the internet and download an emulator. It's not illegal as long as you own the physical game itself, because technically it's a "backup" game. The chances that nintendo will pursue you are zero to none. They only go after the big companies, not the little guy... if they did they would blow through way too much cash trying to make examples of people.
Emulators eliminate nostalgia. I have a GBA emulator though, woo FFTactics!
I blew the hell outta that thing, to no avail. Finally, I youtubed NES flashing screen, and I found out that my "72 pin connector" was dirty. So I followed youtube dude's steps, unscrewed the NES, cleaned the things with some steel wool, and turned it on - BAMMO! Mario and Duck Hunt are working perfectly.