I've had my PowerBook for a few years (1.5ghz G4/ Tiger/ 512RAM/ 15gb fee hdd space on 80gb hdd), and I've never really had a problem with it besides the occasional beach ball of death. However, in the past week I have had two complete system freezes. What I mean by this is that the cursor stays stationary, the computer won't sleep when I close it, and I have to force it to shut down by holding the power button. This happens at strange times (last time I just had Safari and a couple finder windows open, before it was Word and iTunes). What I'm wondering is, is this a problem to be worried about? I haven't had crashes like these since system 9, so it kind of perturbs me to be having them now. I'm hoping they're related to my ridiculously small amount of RAM, but I would hate to upgrade the RAM just to find out that my logic board is going or something like that.