windows product activation error 0x8007007e

[Chriso]

I have had a problem with my comouter;
unmountable_boot_volume, I took my computer to someone and
now this error doesn't appear, though when I go to log in,
I recieve a new error;

windows product activation
A problem is preventing windows from accurately checking
the license for this computer
Error code: 0x8007007e

If anyone could help, it would be greatly appreciated.

Thank you