Hi. A few days ago, I updated our iMac from 10.5.4 (which was working great) to 10.5.6 . After the update, the computer often froze when I put it to sleep. I would put the computer to sleep, the screen and hard drive turned off, but the fans stayed on. The computer wouldn't respond to anything at that point, so my only choice was to force a power off by holding the power button. It didn't always have this problem and I think it might be related to Front Row. Repairing permissions didn't help. Last night, I tried to avoid that problem by shutting off the iMac after using Front Row instead of sleeping it. Same problem, computer shut down (mostly), but the fans stayed on. I forced a power off. This morning when I woke up, I turned the computer on. I saw the spinning wheel like normal, but the wheel froze right before the screen usually changes to the blue background. So after a bit of waiting with no progress, I forced a power off. I turned it on and got into OS X, but it took about twice as long as it usually does. It took about as long to start up when I got home and Firefox ran kind of slowly right after boot for a few minutes. Now it's running okay. Does anyone know if these problems could have been caused by performing an "Upgrade" to Leopard rather than doing an "Archive And Install"? What would be the best way(s) to get the computer running smoothly again? Thanks.