Computer display doesn't work

Rolf Rince David - Updated on Sep 6, 2017 at 11:59 PM
Hello, Ive assembled an old pc with new motherboard . When i tried to format it with windows Ive an 80Gb hdd but it only shows 11gb So i couldn't install i dont understand why. later that day Theres suddenly no display to the monitor the light blinks , keyboard and mouse works ,cpu fan works ram works But no display , i tried another psu still nothing. Whats the cause ?