Mochabomb

Panda Antivirus Control Panel -enable and settings keys greyed out
I ran into this with a a customer - turned out the issue was remaining pieces of Norton Internet Security was killing the Panda config script iface.exe.

Solution: use rnav.exe at Microsoft’s site or find it at Symantec.com
After this, Panda should work - or else reboot and if necessary reinstall Panda.