Monitor powers but goes to sleep

had the monitor trouble that was fixed by other using the power button trick (holding down etc) didn't work for me twice.

also cleaned the ram cards. also didnt work for me.

have a powerful gaming puter bought from techie son. two years now. strong puter. suddenly timing with the monitor going to sleep after normal seeming starting with icons on screen like usual: analog/hdmi then sleeps.

New noise is a rythem sounds like koo koo kachoo and repeats durning startup for short seconds and stops just when the monitor goes to sleep. so it is related.

computer / monitor hooked up with hdmi cable. also tried the vga. tested monitor on standby computer and it is fine and dandy. hdmi's on back of puter and one on front. cable tested and works but no hdmi used engages the monitor of course. same thing always happens....goes to sleep. over and over while i click it back on with the power button. it's the computer as stated not the monitor.

computer seems just fine and runs great and strong as before this kookoo noise. i've spent two days cleaning it meticulously too. checked everything for a tight fit etc!!!!!

so i have video of sound. pics of monster puter if necessary. i need to solve this cuz my life of course is on this and no recent back up due to death of grandson. now i need his pics in this puter!!!

hope you can help so i don't have to take it to a shop. thank you, bless you for your time!