so, i've had a number of problems lately with my PBG4 867. it started when my hard drive crashed and got an irreparable repair. I was able to reformat it zeroing all data, but i do not have faith that this fixed it 100%, so i ordered a new hard drive. I installed a new 512 MB ram chip in it and then installed osx tiger on my external firewire drive to run my computer while I wait for my new hard drive to arrive. well, everything appeared to be running fine, then I was upgrading all the system software and my airport connection was lost while downloading. half the software was upgraded, the other half was not. now, the airport cuts in and out, and when the mac is on, none of my other computers access the wireless hub properly. also, occasionally i get an error at startup where it goes to open firmware and says invalid memory access. I'm not sure what is going on at all. anyone have any explanation for the invalid memory access? the airport not connecting properly when all other computers can access the internet fine (except for when the mac is on and trying to access the internet.)?? this is baffling. it seems to boot much faster with the new ram. but i am thinking about putting the old 256mb chip in to see what it does. never got the invalid memory access until now.