I have a optiplex 740 tower and a 15 inch lcd flatpannel monitor with a VGA slot. it is not the optiplex 740 stock monitor that comes with it. I tried plugging it in to the optiplex 740's VGA slot but it rejected it saying "use the specific cable and graphics slot it came with" which I am assuming is DVI. So I am wondering if i can just buy a specific cable to hook up this monitor or do i have to buy a whole new monitor with a DVI slot in the back of it or just the cable with oneside vga and the other DVI. Also I have looked at a lot of pictures claiming to be Dvi slots but they seem different then the one appearing on back of the optiplex 740 which seems to be connecting to the radeon graphics card. If I could see a optiplex 740 hooked up from the back view that would pretty much answer all my questions here on what needs to be purchased.
You will need to buy the cable that is one side VGA and the other DVI.