Hey, was looking for a little guidance..my prebuilt is about 4 years old with no problems when out of the blue it yesterday turns on but monitor is black with no post..I’m just wondering what would be the more obvious things to try or what you guys thought..it seems so weird, it worked fine earlier in the day and then turn it on later and nothing..the motherboard lights up still and all the fans spin inside the case, appears to be on but no feed to the monitor..any help is much appreciated, thanks..