I was having constant crashes on OS X. Tried the common approaches with no luck. Then I purchased an install disc for 10.6. Erased HD fine (zero out data) with install disc's Disk Utility. Installation stuck after some random little process at the very beginning. Repaired HD fine (verify & repair) with install disc's Disk Utility. Installation stuck after another random little process at the beginning ("Retrieved...pkg.iChat"). Sometimes, when I boot it from the DVD and look at the Disk Utility, my HD is named "Media" (total size 0 bytes). If I let the computer rest for a while (half an hour or so) before turning it on, my HD appears normally (MATSUHITA 250GB, something like that). fsck says it's ok, PRAM/VRAM are zapped. All hardware came factory-installed. Thanks.