After running fine for almost a year, my computer- Amd 8320e, gigabyte r9 290x, gigabyte ud3p motherboard and an EVGA GQ 650w psu refuses to start. It is in a homebuilt case and I have tried disconnecting the power button and shorting the contacts with a screwdrive (this has worked reliably before) but you no avail. The contacts are live: I have checked the 5v difference across them- that disappears if the psu is turned off and draws o.5 milliamp when an ammeter is used between the two contacts. Does anyone have any idea on what is wrong? The psu doesn't seem to turn on when it should: the fans do nothing when turned on, despite eco mode being off.