I've just finished building a new gaming PC and cannot get it to work somehow. Every time I power it up everything seems to work but there is no display, just a black screen. I've tried testing all the components apart from the processor and ram with other computers and they're all working fine. I bought the motherboard from amazon warehouse and it had slightly damaged pins but I sent that back and got a brand new one and I still have the same problem. The processor was delid and purchased on ebay from a legit seller. I've contacted him for a refund, he seems positive that the processor was in perfect working order. The problem is that I can't find any computer shop with a coffee lake motherboard to test the cpu itself and the seller wants proof that it is broken. I'm not sure what else could be wrong with the computer. If anyone has any suggestions then that would be great. The full specs for my pc are below, thanks.
Gigabyte geoforce 1080ti turbo edition 11gb
Intel i7 8700k processor
Asus 1151 socket Z370 Chipset strix D4 mini itx motherboard
Samsung 860 evo 1tb ssd
Corsair vengeance lpx 16gb 2x8gb DDR4 3200MHZ ram
Corsair RM650X psu
Corsair carbide air 240 case
Corsair H100i cooler
Gigabyte geoforce 1080ti turbo edition 11gb
Intel i7 8700k processor
Asus 1151 socket Z370 Chipset strix D4 mini itx motherboard
Samsung 860 evo 1tb ssd
Corsair vengeance lpx 16gb 2x8gb DDR4 3200MHZ ram
Corsair RM650X psu
Corsair carbide air 240 case
Corsair H100i cooler