MSI FM2-A75MA-E35

I´ve been using for about 7 years this system I ( self-taught ) built : Motherboard MSI FM2-A75MA-E35 (MS-7721) AMD Athlon(tm) X4 760K Quad Core Processor 16Gb memory (x2 8Gb DDR3-1600) My graphic card is a fanless NVIDIA GT 710 4Gb low profile, which I use with two screens. A 120gb SSD...

I have a hp a6228x im trying to fix up for the missus, I upgraded her from her older pc. Did the upgrade in steps, checked to make sure everything works. Ram works good, PSU works good, still booting.. put in the graphics card (( which is confirmed good on another pc)) aaannnddd... nothing. The...