Arknaus :
would the GTX 750ti need to be plugged into with one of the power supply cords? because I don't think my PC has one of those, also is the wifi card necessary if you have wired wifi? also are the plugs on the GTX 750ti needed to be plugged in? (these things
https://gyazo.com/15f88e649f8206efc7389c96368e3298 )
That card doesn't need a power cord, it gets all of it's power from the motherboard.
You don't need your wifi card if you are not using it, simply remove the card....it might pay to go into device manager 1st, find the wifi and disable it, that way you shouldn't get a warning about device not found once it's removed.
Those plugs on the back of the card are the display outputs, you only need to use the one for your monitor, you said you have a VGA cable, so use that one and don't do anything with the others.