This is a very common problem after people add a hdd/ssd/gpu/ram/move the cables inside or just move the computer physically. It’s a short. You can try openeing it up, moving the cables around a bit, but it that doesn’t work, try this:
1. Unplug from wall
2. Take out your ram
3. Take out your Cmos battery
4. Unscrew the screws in the motherboard, just a little bit so you can move the MB around a few microns. (Don’t take out the screws entirely, just loosen them)
5. Press and hold the power button for 10 seconds.
6. Wait a few
7. Put the battery back in. Put the ram back in, turn on the monitor, plug back into wall and press power. It’ll turn on. Carefully tighten the screws and you should be good to go.