Hi there. I'm a bit new to MacRumors. Please bear with me if I posted on the wrong forum. I bought my iMac December of 2007. It has lasted me a good two years before it started to glitch. I always used my iMac to browse the web, listen to music, and chat at the same time. It did this very easily and without choking. But, recently, it was glitching. At first it was the occasional beachball. It had happened before, so I didn't think much of it. Then, it got worse and worse, until I couldn't shut it down normally. I left it alone for about half an hour, and it still was frozen. I forced it down, and turned it back on. Applications randomly crashed so then I forced shut it down again. It would not turn on again. I got to the start up chime, and the pinwheel, but even after half an hour, it did not turn on. I took it to a Genius a few days later. The young lady was very helpful, and told me the options I had if it wasn't fixed. Thankfully, she managed to fix it. I took it back home, and it started to act up again. I took the Genius's advice and used a recovery disk to do a repair from Disk Utility. The Verify resulted in errors, but the Repair never started since it kept looking for the disk. I brought it back to the Genius. He did the same thing, but wasn't very helpful as towards my options. He said the only thing I could do was a reformat. I reluctanly accepted it. I didn't have a backup, sadly. I bought an external to avoid this again. Lesson learned. I took the iMac home and then set up Time Machine. My friend tells me that Time Machine could run in the background no sweat, so I went on to download some of my more used applications. I started up my IM program and then Safari, but it froze again. The same smyptoms, beachball and everything. It's been about twenty minutes ince I've written this and it started acting up. The only thing I can do is click the little Time Machine clock on the menu bar near the clock. Any idea what it could be? The Genius assured me that the Hard Drive is fine.