Last night the graphics of my pc went pixelated. Tried the repair options but nothing would work as in I could not use the options as the system said I needed to login as admin but it says there is no admin account. Today I put another graphics card in and this cleared up the pixel problem. However the system will not run and I can still not use any of the repair options. I even put a windows 10 usb stick in to try a repair from that but it does not even see it. 

Spent hours on google on another computer but nothing has worked.

If you have some idea as to what is going on please reply as your help would be most appreciated.