Yesterday when I turned on my PC the fans began to spin as usual but my monitor did not display anything. I tried various troubleshooting techniques (including trying a different screen and cable) but to no avail. When I woke up this morning to continue the troubleshooting process the computer will not even turn on. Upon pressing the button absolutely nothing happens. I have tried reseating all my components but this does not seem to have solved it either. It's worth noting that the night before I began experiencing these issues, when shutting down I removed the power cord from the PSU instead of shutting down the PC conventionally. I don't know if that could have caused this somehow.
I have noticed however that after about 20 seconds of plugging the power cord in, it turns on for a split second (the fans begin to spin and I see lights on the motherboard, but probably for only a tenth of a second).
Does anybody have any ideas of what could be wrong? My best guess at the moment would be the PSU, as over the last few weeks the fan wouldn't spin, and I would have to restart for it to start spinning. I can also hear a feint high pitched sound when I plug the power cord into the power supply, however I'm not sure whether this sound was present or not when the computer was functioning correctly.