Leaving a game cartridge inside your NES, then putting it away for awhile will stretch the 72 pin connector. The next time you want to play, the connector will be stretched, and the connection with the game won't be as good. You'll get the all too familiar blinking screen.

I am not responsible if you read down this page any further.....

I own 4 original Box-style NES's. I bought 2 at yard sales. Both of them had cartridges stored in them for a number of years, and their 72-pin connectors were needless to say, streched out. So i took apart the systems, and disconnected the 72-pin connector from the system. I had a miniscule little flathead screwdriver on hand, and was able to methodically bend each and every little pin back up a little ways. It worked a bit better. I could tell when i put a cartridge in that the game had a snugger fit. If only the connector wasn't corroded from people BLOWING on the games, i'd be a VERY HAPPY MAN, with another flawless NES system.

I wouldn't advise others on doing this unless they're maybe 15 years old (the age that I think kids finnal realize what the heck is going on around them.) Remember, those pins aren't the strongest little things, so dont bend them really far upwards, it might break off!!