Checked all that and problems persist.
hmm.......
have you posted or can you post your DXDIAG report info for your PC
and list how many processes you have running, list how many USBdevices/periphals you are using, and your computer specs & PSU
also, do you use a powered hub
stuff like this can become tedeous to track down and figure out.....
you could be starting to lose a Serial bus controller or channel on the MB could be starting to go south on you.....
hell, it could even be a cord on one or both of the game controllers got pulled/stretched/yanked, etc.... ( like stepping on or roling over them with your chair, etc... )
not that it is any of those things........ but need more info at this point
TC