video engine stopped working on mac mini 10.12.6

I am in the middle of a project and my video engine stopped working.I don’t see it under device menu and when I go to device set up it says update your graphic driver or use more efficient graphic card .until now it was working…Could anyone help me with this situation?

mac mini 2011 i7 2.00 qc 16gb ram

Hi Ithink is the heat problem
after cooling it down and restarting
fixed.And it is the hardware problem .