Mac Mini with Lion wont start after Power failure...help! I was working on my Mac mini (Lion 10.7.2) when the power went off. When the power came, I started Mac Mini. But it keeps on showing grey screen with activity indicator forever. It wont start the system.

I have tried Repair Disk, Repair File Permissions, but still it wont start.

How do I resolve this issue?
Apple has guidelines explaining what to check for:
Mac OS X: Gray screen appears during startup (support.apple.com)