all ports bad for mounting external drive

My Powerbook G4 will not mount any hard drives on any port. It was working fine, then a cable slipped and a hard drive was unplugged from the Firewire 800 port. I got the Apple warning screen. Since then I have trouble shot by checking that the hard drives work on other macs. And, trying to mount the drives via the firewire 400 and USB ports. Nothing. Rebooting did not fix. Is this a hardware problem, or software?