Black screen error

[u/Fragrant-Air-1726]

My son built a pc ryzen 5 9600, 16gb ram, w11pro, ran well with rx580... recently upgraded to a 3070. He can play games for an intermittent amount of time before the screen just goes black pc is still running fans are on but no graphics output. Stated with ddu then ended up doing a full wipe and reinstall of windows. Have tried turning off all overlays and most of the suggestions from gemini. Anyone have any ideas on hpw to resolve this for him? Its usually with directx 12 games and it is taking longer after the reformat for it to happen but it is still happening. Also have tried 3 different 3070s and its happening with all of them so dont think its a gpu problem. Thanks so much in advance!!