wireless mouse/keyboard not functioning

my Dimension 9100 was brand new at the beginning of this past August, and everything worked fine up until I moved back home from college for winter break. Now, my wireless mouse doesn't move at all, and it's not a battery problem - I've changed the batteries. this has never happened before. the keyboard worked up until today, when I logged on to see if my mouse somehow would miraculously work. now my keyboard doesn't.

this is incredibly frustrating, and I'm worried that something may have gotten messed up on the drive home. however, I did make sure that the mouse and keyboard were packed so that they wouldn't move or fall. I have no idea what would have caused this problem - any ideas?? please help!