Hi, I have a G4 Ibook that I desperately need to keep alive for another month. My doctoral quals are next month. Everything is backed up, but I have no time to replace the computer. It's running ok, but a terrible sound is intermittently coming from the left side of the keyboard--probably the HD? It varies in loudness but it sounds sort of like a rotary grinder--there's a real sound of harsh friction. It comes and goes. First, can anybody give a possible diagnosis of what this is? Second, is there anything I can do to mitigate the problem, even for just a few weeks? Third, is this terminal, and what's the prognosis? Thank you!