Hi I Just Bought A vga y cable i'm using a msi gtx 1050ti i can't find my second screen in my screen settings i try updating my graphics card but still can't find my second screen.Is it the graphics card problem or is it the cable
A Y-cable will send the same video to both screens.
To show different things on two monitors, you need two separate cables - one for each monitor. (The exception is Displayport which can sometimes be daisy-chained. e.g. PC plugged into monitor, second monitor plugged into first monitor.)
your video card has 1 dvi, 1 hdmi, and 1 DP. Plug one monitor in with just a dvi cable, and the other monitor with a DP or HDMI to dvi cable. Each monitor has to have its own cable coming from a port on the video card. you cant use any splitters/ y cables