I was rebooting my early 2011 MacBook to run a hardware test on system boot using the shift key. It all went well and the hardware test was accomplished. I rebooted as usual and I get a circle with a line through it instead of the Apple symbol.
Regardless of whether I am booting in safe mode it doesn't boot.
I did the hard disk check and privilege repair which had some complains of that got fixed.
I can't get the system to run. I don't know what a reinstall from recovery will do to my stuff or the machine. What's lost?
Here's a picture of the kernel panic: