Machine Check: Failed.....Executive Load: Failed

I have A Bridgeport Discovery 308. I think it is a 1991. I have been running it for about three years, having very few issues. A couple of days ago it was running fine, but the air temperature was getting warm and I thought it was a good idea to shut down. Went to do a tool change to clear the spindle, and the moniter screen "froze", which it has done before. This is usually taken care of by shutting down and then starting up again, that has worked each time before to correct a frozen screen. This time instead of the machine check...ok and then going to the screen with the enable button, I got Machine Check: failed...Executive Load: failed..error code -1 C:/_.

Any thoughts, input, or ideas that will help me get past this would be greatly appreciated. Thank you.