heres the situation...g5 dual 2.0 1.5gigs of pc3200 i have 2 mcally firewire/usb 2.0 hubs hooked up to my g5 with 4 ext. hdd's and 1 ext. 52x cd burner....if i leave my mac on all day when i come back from work 8hrs later my mac is frozen and i have a little screen saying to restart my mac (with the fans blowing at full speed)!!!!! i restart the computer and its fine any clues to whats going? please help!!!!! thanx in advance!