Mac Pro (2009) / Snow Leopard DVD. Having some odd (and very annoying) problems with this setup. Frequently get the spinning rainbow beach ball, apps become unresponsive, no way to restart, have to run a hard re-boot. This usually occurs after about twenty minutes of use. Tried the usual basic solutions: Disk Utility / Repair Disk Permissions (on all drives). Safe (shift) Boot. But this has had no effect, and the problem persists. Wanted to use the DVD Disk Utility. Tried booting from the original Snow Leopard install DVD (and from the same on an external firewire hard drive). BUT it only gets as far as the grey screen Apple logo, with spinning gear and then freezes, every time. Spoke to AppleCare support. They had no suggestions other than to bring the box into an Apple Store. Unfortunately, that would leave me without a critical work tool for a month or so, since Apple stores do not carry any spare parts (to save them money). And I would have to remove all private data etc. So, a big pain. Note. The system files and applications are on a 240Gb 6G SSD (from OWC). Everything else is on a pair of internal 2T HHDs (Raid 1). Also, backed up via SuperDuper and Time Machine. Ideas and suggestions appreciated, thx.