Question No signal from GPU , works on integrated from MB. Tried all threads to solve.

Nov 4, 2021
Hi guys
So i got simple problem here, my pc starts but no signal appears.
Fans spin, leds light up normally, even mouse or keyboard appears normally with their leds. I got no beep from my PC (but i havent got that even before).

I tried:

Another cables (HMDI, VGA, DVI) (no solve)
Another monitor (no solve)
Try this on monitor i use (monitor worked with another PC and PS4)
Exchange supply cables (no solve)
Reseat GPU (no solve)
Put out and in CMOS Battery, later i exchanged her completely (no solve)
Put out GPU and try on integrated (WORKED, but no solve to my problem, as i know my GPU is normaly working on another PC ´s)
Cleaned RAM and other parts ports from dust (no solve)
Later i tried put out all parts and put in back again (no solve).

This problem is complicated even more after i tried instead of 6pins connecting to my GPU i used 2x 6pins
My pc then started up normally , and worked for 2 hours. Then , i opened one of my games - CS:GO to test it - and after 2 minutes i got blackscreen, i heard lag sound from headphones, screen gone black, PC acted like restart and now my problem is even on 2x 6 pins instead of 1x 6pin. WTF?

Am really sorry am writing here, but I got no another option , as i need this PC and new one (even this old setup) is not possibility in actual situation.
Am going to try run it on integrated and am going to uninstall drivers of GPU. I will delete my post if it will work, or update it to help others.

My setup here:
GPU: MSI R380 Gaming 2G
CPU: AMD 6300 3.5GHZ
PSU: Zalman ZM 600 - II LX
2x 4GB RAM - Hyper X
2x Disk - Seagate and Corsair, 500 and 1000GB
MB: Gigabyte GA 78LMT- USB 3GB

Please guys help me take a look, if my post is irelevant am really sorry i will delete imidiately.
Nov 4, 2021
Welcome to the forums, newcomer!

How old is the PSU in your build? Is the GPU you have in that system the R9 380 or the R9 380x?
I have 380. To be clear, my PSU is totally new. Never used before, bought from internet. I had problem that i havent used this PC like for year and half, then tried to start it up after that time and it havent work. With my low skills i diagnosed that PSU is dead. So i exchanged it for Zalman and must say, it worked, i used that setup to make needed job i had to for like 2 days, then i havent used that PC 3 months. Then i borrowed it to friend, which had same problem with this PC. He fixed it somehow, but sadly he is on mission in Afghanistam now, so no contact avaible with him for half year. But now i am wondering it really might be PSU to GPU bad connection?