Blank screen after installing a gtx 550 ti

[randle]

just built 2 computers exactly alike. one works one doesnt,here is specs
corsair 850 ps
gigabyte 990f xa-ud3 mobo
8 gigs ram
1 t hd
gtx 550 ti
6 core 3.8


heres my question cause im new to building but i took precautions ( rubber gloves,touching case,mobo on top of the box) what is the most common mistakes that gives the the black screen? the card's fan spins and when i unplug the monitor it says no vga detected,when i plug it in the monitor goes into power saving or sleep mode

 

[pratik borkar]

hi,

Did you try to insert the graphic card of working pc into the not working one's? Also try other probabilities such as:- change vga cables or change monitors.