We recently upgraded to cs5, and for everything good that it does, it also has a few weird quirks. The most notable is that using the space bar to temporarily select the move tool (the one that looks like a hand) does not work. This is a known issue, but it still sucks. The only workaround is equally quirky: shut down your web browsers. I can’t say why it happens, but hopefully that one trick will keep you from throwing your machine against a wall. I was really close!