my monitor has a 15 pin d sub vga and 2 hdmi connections but my graphics card the radeon 7990 only has 4 mini display ports and 1 dual link dvi port. What should i do?
Make sure your monitor source is set correctly (to HDMI, if that is how you are connecting). If there is still no signal then it could be that your GPU is not detecting your monitor.
One HDMI connection into your monitor should be sufficient. You don't need to hook up every connection on your monitor to your GPU for it to work. You only use those extra connections if you want to hook up different sources to one monitor (like a second computer/laptop or something).
Make sure your monitor source is set correctly (to HDMI, if that is how you are connecting). If there is still no signal then it could be that your GPU is not detecting your monitor.