20" iMac G5 2.0 GHz, 512 MB RAM, SuperDrive, 128 MB Video RAM, 260 GB, Airport Extreme, Bluetooth Mac OS X 10.4.4. Just recently, a week or two after updating to 10.4.4, my Login Window has stopped appearing after waking from sleep or after Sceen Saver. The computer just wakes up to the Desktop. The screen takes a few seconds to turn on the brightness, too. First it's black, then dim, then it's bright.... What's going wrong?