PC ( AMD Radeon HD 7770 )

PC lights up for a second but doesn't start, (RAM, CPU, Motherboard definitely work as they were tested a year ago). Bought this from a yard sale over 3 years ago but never used it so I don't know if there is anything on the hard drives or how long the PC has been used for. *Will not deliver, but can meet up at a location near clondalkin* Gpu: AMD Radeon HD 7770 GHz Edition Cpu: FX 6300 Ram: 12GB DDR3 Motherboard: ASUS M5A78L-M/USB3 Socket AM3+ Hard drives: 2 Barracuda ES 750gb drives Psu: Arctic blue+ AD-E850AE-A5/A6 850w Fan Case: Unknown, not in the best condition.