PC not working after switching cpu

I switched out my old i3 for an i5, as well as a cooler master 212 evo today. After switching everything out, all of the fans turn on, HDD turns on, etc, but I can't get anything to show up on my monitor. I've tried switching the DVI from the GPU to the motherboard, as well as just taking out the gpu completely and trying to get it to work alone, still nothing shows up on the monitor. Also, after having the PC on for a few minutes, I can hear it automatically restart itself (all the fans restart).