Mid 2007 iMac keeps going to sleep after HDD upgrade. I recently upgraded my imac's hard drive to a 2tb drive from a similarly speced 1tb hard drive, both installed by me. After installing snow leopard and getting everything back up and running, it started to crash/sleep every so often. And then it started doing it every 2 minutes. Thinking it might be a heat issue, I got temperature monitor installed. I immediately received readings that were 'off the charts'. An average reading of about 125F and some readings saying they were as high as 165F. The iMac had been on for a few hours already, so I immediately just did a quick hand test all over the case. No more warm in any area than ever before. Any ideas? I have not ran a hardware test yet, but I have reset PRAM and the like. No difference. Could it be that I didn't connect the heat thermometer back up correctly? Or that I placed it on a bad spot on the HDD? I am going to open it up in a little while and see what is going on, but I wanted to see if anyone had any thoughts before I went ahead.