I'm having problems with an old g5 tower (late model 2004) running osx 10.4. I'm unable to type anything but the mouse attached to the keyboard seems to works fine using all USB ports. Whenever I try to use the sound keys on the keyboard the volume goes to extremes from mutes to highest settings, and the volume graphic that appears on the monitor won't disappear. Sometimes the sound won't turn off and the monitor will start flashing as if it were stuck in a loop. Any suggestions?