Help! I Dropped My PC and Now It Won’t Turn On

So, I cleaned my computer last night, taking it apart to get rid of the dust. It was working fine after that. But then I accidentally dropped it while trying to put the cover back on. I didn't drop it far, just from its standing height. Now, my monitor says 'no signal' and goes dark, although all the fans are still running and the power light is on. My keyboard, mouse, and microphone have no power at all. I checked the connections and everything looks good. I'm not super tech-savvy, so I'm not sure what to do next. Should I troubleshoot it myself or take it to a repair shop?