I recently upgraded from a 60GB hard drive to an 80GB hard drive(@5400rpm instead of 4200) and now the trackpad doesn't work-meaning no response whatsoever. Has anyone else experienced problems with their trackpads? I would greatly appreciate some help, since I have to plug in a usb mouse every time I use my PowerBook, which defeats the purpose of buying a super-portable computer. Oh, the Powerbook is only 4 weeks-old . Any suggestions would be helpful. Thanks!