Start menu driving me insane...

Hello all you smart people. Please help. :cry I have an HP touchsmart desktop that has decided to drive me crazy. The start menu just keeps popping up on it's own for no apparent reason. I have run everything to my knowledge that might help, I have popped off my start menu keys to see if they were stuck, I attempted to try another keyboard but the one I have has the incorrect plug to check it out. I just don't know if it is something in my comp or my keyboard or what. The computer is slow on and off, some days it seems to work fine, others it drags. That doesn't bother me as much as this menu that is now showing up once every 10 seconds or so making anything impossible and annoying. Please help. Thank you SOOO much.