Evangelist

i have a not too old computer i set up, and recently the monitor for this computer has been turning off at random times. the light on the monitor turns yellow and i cant turn it back on until i wait the monitor to fully turn its self off.
the computer has been set up for a while but just recently its been acting like this. i thought it might be a trojan, virus or worm, but i scanned the computer with multiple programs but the clean up was to no avail. can anyone tell me what i should do? do i have to purchase a new monitor? because i dont want to buy a new monitor and it turns its self off too. if u require specs on my computer just tell me