MacBook Air drive won't boot up after repair, hard drive is locked

Hi, I recently repaired my old Macbook Air keyboard. After putting it back together I am getting a white screen with Apple logo and spinning circle. After pressing CMD+R and trying to repair disks in Disk Utility I get this message.

Disk Utility stopped repairing “Untitled”

Disk Utility can’t repair this disk. Back up as many of your files as possible, reformat the disk, and restore your backed-up files.”

Error log shows “incorrect block count” for “kernel.log”, “secure.log, 2015.01.01.asl”, “2015.01.01.G80.asl” and “2015.01.01.U8.G80.asl”. Also it shows “invalid index key”

When I try to reinstall OSX Lion, it says I cannot because the hard drive is locked.

I have no important data on here, just want to be able to get the disk to boot.

Any help would be much appreciated.

Thank you!