Hi, I have iMac 27 Mid 2011. After pressing the power button, I can hear the startup chime, then apple logo shows up, then animation "ring" and then everything is gone and iMac stuck on grey screen. You can watch the movie with this issue here. Here is what I did: 1. SMC reset 2. PRAM reset 3. Safe boot - it ends on black screen, sometimes on grey and sometimes on blue. Here are the movies movie1, movie2 4. Hardware test - no fault found: 5. Boot from install disk - the movie here 6. Recovery option acts the same as safe boot (3). 7. Boot on another Mac - I removed the hard drive from my iMac and attach it to other iMac using a USB adapter. The system starts perfectly! I made disk check and permission check using the disk utility - no faults. Still no luck with my iMac Can anybody help mi with that?