Sounds like a driver issue. Be sure to ask the maker which drivers to use.
I am using a laptop and am experiencing mouse and keyboard delay while playing games. So far this has happened in the games syndicate, FEAR 3, and Diablo 3 that I've played and hasn't happened in a few I've played. Whenever i minimize the game and open internet or anything I get no lag no delay or anything. I've tried setting the game to high priority in task manager. I use Microsoft mouse and keyboard center driver and synaptics touch pad and have tried disabling both and playing with no change and reinstalling both. I also have AMD Catalyst driver which mainly effects graphics card and have messed with all of those setting and reinstalled it. I've also messed with many keyboard and mouse settings and little change. The only thing I've seen that drastically reduces the delay is whenever I change the resolution in a game to lower (800x600, drastically low) there is barely any delay at all.
~The conclusions I've come to are that there is either a problem with my graphics card (whither it being to bad for these games or whatever), there is some kind of driver problem, or there is a problem my frame rate.