If your Nes does the same as the video below (Blinking red light)

it means that the NES cannot read the cartridge.The good news is that this is fixable with a  good Mod/repair that will make your NES working for another Lifetime!

With that Mod/Repair there is no need to push down the game cartridge and you are also getting a region Free Nes – meaning you can play US/JAP/EUR games!