External Monitor VGA and HDMI problem

Suddenly yesterday my external monitor stopped working via mini-display port to HDMI. I'm sure it's not the cable, plug or display since these all work with another MacBook Pro. This had been working for almost a year when is suddenly stopped yesterday. When i plug the adapter into my computer the screen flashes blue and goes back to how it was, monitor shows no input. Is there any solution for this,

Also I now started using my old mini-display port to VGA set up which I bought first. I switched to HDMI since I was getting 1-2 seconds of black. This would happen multiple times in a few minutes and then not happen for an hour or two. This still happens now any fix for this?