So here's the situation. My gf is asking for my help and I don't know what she's talking about. She said she wanted to fix her monitor that seems blurry by changing cables. She's currently using a VGA cable and when I looked at her system unit, there is no DVI input but there is an HDMI. But, on the monitor there is a DVI-D with dual channel. What should I do? Buy a hdmi to DVI-D or VGA to DVI-D? Forgive me, I'm not that computer literate.