so i got this computer form my friend and he wanted me to hook it up with some programs and stff, but the mouse pad wasnt working. i took the thing apart and switched out some ram chips because someone had taken his 4 gig one and left him a 2 gig so i felt like being nice. anyways i put the computer back together and now the keyboard blatantly doesnt work, and he mouse pad is still messed up to. did i miss a wire or something? the keyboard worked fine before i took i apart mind you. i know i messed something up but i cant figure out what, please halpp