Hi folks, Ok...so my powermac g5 dually 2.0 had some bad ram. it was on tiger b/c there was a few apps that aren't leo compatible yet and it was running perfect. As part of my testing, i upgraded from Tiger to Leo. Even with the ram out, I still the locking issue and the techie said that bad ram can cause other corruptions so, his advice is to do a clean erase & install. My stuff is backed up so i'm not bothered about doing it. Except, I'm not sure which OS to put back on? Can I go back to Tiger after being on Leo? I popped the Leo dvd back in for the fun of it (before I thought about going back to Tiger) and I didn't see the erase & install option. I'm pretty sure I remember seeing it when I re-installed Tiger (which was a few steps before reinstalling Leo). Any ideas? Cheers, keebler PS. I should say that my mac pro is also still on tiger and it's my main working machine. The G5 is for photoshop, nikon scanning and occasional final cut pro editing and mpeg2 compression.