Help! Powerbook G4 major probs

[johnnyig]

Hi all, My fiance has a powerbook 17in g4 1.67 ghz that I got here just before the intel ones came out. I purchased the apple icare 3 yr plan for her and so far i'm glad I did. After about 3 months of use her unit stopped opening up programs, if you click on any MS office icon it would just bounce on the tray and never open, you would have to force quit the program. Adobe would not open any files she wasnt even able to print. So she took the machine in, the drive was re-formated and all was well, for a little while then the same thing starts happening, and tonight we do an OS reinstall and no sooner do we do a reinstall and put in all the applicable OS updates the same things start happening yet again. I am really at a loss here, I think there is some major hard-drive or motherboard problem with this thing. Any ideas? the os is currently at 10.4.8. thanks! -John