i have recently built a gaming PC and it has worked for about 3 days but yesterday when i got home from a family dinner it wouldn't turn on so i checked all the cables and they were in the right place. i have also paperclip tested my PSU and that's fine so i took everything out of the case and put the motherboard on its box, hooked everything up it worked, put it back in the case nothing, took it out again, put it on its box nothing waited about ten minutes worked outside case. i have repeated this a bout 3 times and always the same result.
can someone help please ?
Are there any metal pieces touching the motherboard? Sounds like the motherboard is making contact with the metal part of the case which causes this behaviour. Check to see if all motherboard standoff screws are present and the motherboard is elevated from the back of the case by a few mm.
This happened to me, a few weeks ago. What seems to have happened is that your GPU has failed. I took my PC to a local IT retailer and they gave my PC a free examination and took out the GPU and plugged in the screen to the Processor (Integrated Graphics) and now the PC powers on again. I still really need to get a graphics card.
It still seems weird to me that the PC didn't start up at all with a broken graphics card. It seemed to refuse to live without it.