This is my first instructable ever, so please be nice!
My buddy was too lazy to look online for solutions, and actually fix his rock band guitar - so I stole it, the game, his other guitar, and his mic. It wouldn't register down strums, and as you know, up strumming an entire song is just no fun.
I have to give credit to Ben Sones from Quarter To Three. His fix was the inspiration to mine. Plus his seems more reliable. http://www.quartertothree.com/game-talk/showthread.php?t=40188