Monster displays no signal and PC keeps rebooting

Hey!
So at first a few weeks ago my pc turned on and my monitor was just fine. However suddenly my monitor displayed a black screen with “no signal”. I then proceeded to restart my monitor multiple times (the power on / off) button and it suddenely received signal. Then just today I decided to tackle the problem by vacuuming the outside and then proceeded to air spray the inside and reseated the ram since that was what was online as a solution. I took out my ram and used the air sprayer to clean out the dust and reseated the ram. I then sprayed that air sprayer into the mother board and all around to remove the dust. Right after I tried to turn on the computer and it then just keeps rebooting itself after 10 seconds or so and my monitor still receives no signal. I’ve also tried to reseat my graphic cards and still no solutions. Everything suddenly happen and I’m still lost on what the cause was.
Thank you!