I'm running a PowerBook G4 12" 1.33 512MB 10.4.11 and 16GB free on the hard-drive. I'm a grad student and I use the computer mainly for word-processing, internet, skype and some specialized linguistic software. Well, I shouldn't use "running" quite so loosely. In the past year the computer has slowed down drastically. I am at the point I can really only run two programs at a time. The slow-down doesn't seem to be in running programs but in opening or closing them. And, forget about trying to shut-down the computer, it can take almost 20 minutes from the time shut-down is selected to the time it finally turns itself off. Boot-up is the same way. Same goes with Safari, itunes, Word, saving files and the like. I am wondering if it would be helpful to reformat (The computer has never been reformatted). I'm in the middle of studying for comprehensive exams, however, and I really don't want to spend the time if it isn't going to make much of a difference. Some of my linguistic software will be huge pain to set up, and, in general, I just don't have the bandwidth to deal with reformatting unless the energy is worth the results. I am hoping to finally replace the machine toward the end of the year (though, I say that every year and never do. Yet, considering, I think this year will be different ). Thanks for any advice.