Are you saying that you installed a new motherboard, added RAM ( are they matched sticks?) a new GPU and a new PSU ?
I'm also wondering if the OS is OEM ?
So i decided to upgrade my gpu(Gtx 560) to the 1050 ti. I installed the new card in the pc and when i turned it on the first time i got a message from the monitor saying there is no video source. I unpluged and pluged the gpu in the pci-e slot and tried again and this time the pc booted but after the windows logo all i got was the mouse cursor and a black screen. I waited 20 minutes and nothing happened. i put back the old card in and got the same thing again. i tried using the onboard video and still the same thing, even after booting in safe mode. What could have happened?My pc is made by HP it has an i5 650, 6gb ddr3 ram(i upgraded to 10gb) a 430w psu and an msi ms 7613 motherboard.