dead powersupply

Hello, My pc worked yesterday perfectly but today it wont turn on. What could be the problem? I have 750w cooler master power supply, had it for 5 years, but now for some reason my pc wont start, so I tried turning on the power supply without the motherboard but it still didn’t turn on, but when...

Just bought a New (open box) Corsair RM Series RM850 80 Plus Gold and when I used a power supply tester on it the pg was 0ms. Is the power supply dead? Is it because I only have the 24 pin and cpu 8-pin plugged in? Or is it a common error with power supply testers?

A while back my computer suddenly made a whining noise and turned itself off, now it wont turn back on, occasionally when I press the on button all the LED's will flash for a split second. I bought a PSU tester and plugged it in, it showed the correct voltages and showed green LED's meaning the...

Hi fellas. So I've got this PC that keeps cycling on and off, every time I turn it on. I've tried reseating the RAM in all possible combinations (and tried just one at a time), cleared CMOS and now after buying a new PSU, tried that one on for size. It's still cycling. Do you have any ideas...