You might try re-installing the mouse drivers; sometimes other software interferes.  I've had buttons stick in the past, and it was always the fault of a badly-written, aggressive piece of software (RealPlayer on one occasion, if I remember right; browser plugins are usually the most likely candidates).  My clock has always lost time, too; it's not a battery problem in my case (someone told me that using the computer's built-in speaker can mess with the clock, but I don't know if that's right or not)-I just re-set it once in a while.

Malcolm