You might have changed some settings relating to voltage or frequency of either the memory or processor in the motherboard’s BIOS. The values that are presently set might not be compatible with your processor or memory, and hence the BIOS report that it is unstable. OC means over clock, where the values of the processor or RAM voltage or frequencies are tweaked higher than its actual operating ratings to run faster than usual. Over clocking is done to gain higher speeds from a slower computer, but if not done properly, it can damage your hardware components in the long run. I would suggest that you reset your BIOS to the default settings by entering the BIOS of your motherboard immediately after powering on your PC. Once this is done, you should not get any errors.
If the PC can’t run on the specified over clocking settings, it will show an OC error or won’t start up.
