As others have mentioned, there are some games that act rather funkily (heh... is that a word?) when CnQ was enabled. A good solution, if a bit annoying at times for the extremely lazy, was to go to Control Panel -> Power Options -> and change power scheme from "Minimal Power Management" to "Always On". Then after playing that particular game (Grand Prix Legends, in my case), I just switch it back to Minimal Power Management.
I don't know if this will work for other games such as Madden 06, but you could try it. And if it works, then at least you can still have CnQ for regular use.