Question PC boots but no display

Oct 13, 2021
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Hi guys got a question for anyone who knows stuff about pcs,
About a month ago now i was cleaning my pc just with compressed air and didnt unplug anything or touch the mobo simply just air cleaned it.
However when i next tried to boot up the pc it would boot, fans work and the RBG works on all the components it should be but there is nothing showing up on the screen just completely black. It doesnt even reach the bios thing so cant even reach bios, simply no activity on the screen. The USB ports also dont work so my keyboard or mouse also dont work with it.
The mobo had a new white light next to the RAM suggesting the Ram could've gone however i tried taking them all out and using 1 at a time to see if that would help but nothing changed.
I have tried different cables, tried a different monitor and just about most of the simple things. I took it to a repair shop and they said it was the MOBO and possibly the CPU were gone so i got a new MOBO and the problem persisted so long story short. I got a new power supply, new mobo and new CPU and yet its the same issue. However on the new MOBO the light for the RAM is off and theres a red one for the CPU now :/
The repair shop said all other components were working such as the GPU and i tried putting the Display port into the MOBO instead but still no signal.
Does anyone else have any ideas of what could be causing the issue?