Games won't load anymore

Weedo

My son was grounded from his computer for while. I removed the power cord and hid it so it wasn't even turned on for about a month. Now many of his games that he previously played won't work anymore. They can be installed but usually wont get to or past the initial splash screen. It's happened with Doom 3, Undying and others. Could this be a registration thing? It really doesn't make sense. This seems to happen far too often.