My computer is ill. It is a great one year old computer with watercooling, but recently it has been getting more and more sick. It started at first, when I overclocked it. all of a sudden it would randomely crash, so i removed all overclocking, which helped, but didn't remove the problem entirely. The computer still crashes during gaming, sometimes it powers down entirely, sometimes restart and sometimes (mostly) the screen just gives out. The screen will power off, the on, and tell me it has no signal. no amount of shutting screen down and back on helps, but if I reset/restart the computer the problem disappears. When I do this, and the computer restarts my wireless internet USB dongle wont work until it has been disconnected/re-connected. As if that is not bad enough, recently an entirely new problem has arisen. My computer wont turn on. The computer does have power, because there is a small power and reset button on the motherboard with LED lights that work, but absolutely nothing happens when I push the power button. I tried disconnecting the computer and testing that everything was connected and secure, and everything seemed ok, and suddenly the computer started, but next day, same problem, som I opened it up and rooted around and suddenly it worked again. then it worked for about 3 days, and then not again. I was frustrated so i pounded the on-button 10-11 times and left it alone. After about 10 minutes of noone touching it, it suddenly came on again. today - again - it doesn't work, and no amount of rooting around, disconnecting/re-connecting RAM, wires, graphics card work. No pounding of on-button work, no disconnecting power cord, waiting 5 minutes the re-connecting power cord works. I've checked for scorch marks - nothing. Checked for water stains from eventual leaks, but there are none. did a lamp test, plug is fine. tried motherboard power/reset button till my fingers hurt - nothing. I have absolutely no idea of what the problem is, or indeed how to fix it... does this sound familiar to anyone?
This kind of problem sounds like the PSU is broken or failing. Try to get a different PSU to test the system, and only connect the motherboard, HDD, CPU and RAM (disconnect all other parts of the system). Then, if it works, shut it off and connect the rest of the parts 1 by 1 (if the PSU you got is strong enough).