17 R4, external monitor suddenly unresponsive

My laptop has been working since 2017 without any issue. Recently I find if I leave the laptop on to do something and come back its unresponsive. The fans are running normally nothing is responding on Bluetooth keyboard or mouse or on laptop keyboard and mouse. I try to ctrl+alt+del to get out of it but nothing responding. It is fairly recent and happened 3 times now. Very annoying as I loose all my tabs and work and need to force restart. Any help would be appreciated.