can't reprogram arduino robot

Hi, my arduino robot is refusing to get the new sketches, i tried in osx mavericks and windows 7.
in mavericks it only reboots and nothing else, it restarts with the last sketch that was uploaded times ago.
in windows 7 i tried to install the drivers that came with the arduino compeller, but nothing happens, windows sees the control board but says it has no drivers (i installed the drivers with the program inside the drivers directory) i tried also to install the drivers manually but windows says it can’t find any suitable driver.