Monday evening I noticed that my mac mini, though working fine, was displaying the time as Saturday, 3:01 pm. Whenever I tried to open date and time preferences, I just got the pinwheel. I figured I would reboot the system, since I don't do that very often. It hung. And hung. And continued to hang after multiple reboots. I finally booted from the Snow Leopard disc, ran the disk utility, and had it verify the disk. It said the disc needed to be repaired. So I hit repair and after a few minutes and lots of "Invalid node structure" and "Invalid record count" statements it said the disc could not be repaired, that I should erase and restore from backups. I had my time machine backups on an external hard dive, so I wasn't too worried. But after restoring, it still wouldn't boot, and I had a repeat experience with disk utility. So I restored the next older backup. Same story, except that disk repair got to something like "rebuilding boot partitions as required" (or something like that, I forget the exact message) before telling me the disc could not be repaired. I have now worked my way back through a week's worth of nightly backups, back to before I even installed the recent OS update, and have the same experience every time. So am I likely looking at a hardware problem at this point...?