Left Alt key half working?

I wasn't sure if I should have put this in the gaming section or in hardware section, but I figured since it doesn't happen exclusively to the game I play I figured i'd try here.

I came home and set up a dual monitor for my computer, mainly so I can still do things on the 2nd monitor whilst playing a game. Half way through trying to figure out how I could get things where I wanted them my left ALT key decided to stop allowing me to alt+tab. If I hold it down it gives me the little window that allows me to switch between my programs, but it won't actually go to them it just stays stuck on that selector. Makes no sense to me due to if the ALT key was dead I wouldn't be able to get half way through alt+tabbing correct?

Anyways, it also stopped working as my push-to-talk on my Teamspeak 3 Client. Again, thought maybe the key was bad BUT it still works as a push-to-talk on my Mumble client.

What in the world is going on with this stupid key? I doubt the dual monitor has anything to do with it, but like when trying to find truck issues it's better to list everything that's been done just in case.

For me the left alt works intermittantly. It has something to do with what has focus or something.

This is really annoying and makes it impossible to write code in visual studio.