black screening

So i recently purchased a new pc as my old laptop was breaking down. https://nzxt.com/product/starter-pro is the build and the place i bought it from. I have not added any custom parts to it. Im also fairly computor illiterate so I dont know the best ways to fix these kinds of issues. Problems...

So... I Was Browsing My Local Used Stuff Website :D And I Found Some Used GPU's And Its Really Hard To Choose Which One I Should Take.... I Can't Choose Of 6 Options... 1) HD 7870 I Saw Great Reviews Of It, And It Costs 80$ (used) 2) R9 270 65$ (used) 3) 950 mini 85$ (used) 4) Rx 550 96$ (used)...

Hello, I have an urgent problem with my PC Yesterday I put it into sleep mode and today it won't start. It has never happened before. The LED flashes signalising it is in a sleep mode but nothing wakes the PC up. I tried: - ctrl-alt-del to turn it on, but no effect - using anything to turn it...