Mike's computer freezes up when it's coming out of sleep mode. Leo says that it's a common problem with computers, especially Macs. But even Windows machines have this happen. It's like the computer is "groggy." Sleep puts the computer into a low power mode but still feeds power to the RAM to prevent the user from losing information. It can be problematic, though. Hybernation has it's own similar issues. Leo suspects that since the mouse and keyboard work, that the computer hasn't really crashed. He should do a Google search for the specific computer model. That may give him more clear solutions. From the chatroom, there's this article which may help find a solution.
Leo also suggests a BIOS update for the motherboard, which may address it. Most likely, it's the motherboard itself. He should check the BIOS and OS power settings. He should update the motherboard and video card drivers. He should choose to not let the hard drive go to sleep, and perhaps just disable sleep altogether. It really could be anything at this point.