these problems could also maybe be a keyboard problem. I replace dell keyboards all the time at work. The drifting mouse problem is definetly a common dell kybd problem. i would say isolate and other programs, check the mouse settings in the alps util, control panel.. lastly you could d/l the dell diagnostics program, run the symptoms test (only with the gui diags) and run the drift test dude..

let us know if you have any luck