When he remvd the ram &put it bak on..it bootd showing the mb model screen name and two options 1)press del for setup and 2) tab for post...whichever he tested he got reboot and select proper device
looks like the resolution went out of sync, which OS do you use?
do you get POST screen? if yes then start OS in safe mode and reset display resolution to the native resolution.
he got it when he remvd the ram one time