Unity Web Player telling me to install. Suddenly. NEED HELP FAST!

Ok, so i have this problem: http://answers.unity3d.com/questions/256216/webplayer-telling-me-to-install-but-its-already-be.html

But i have no idea of anything coding or html related, so please help me.

What happened: I played this game Rush Team for quite a while, everything working. Then suddenly it stopped working, and now its telling me I dont have unity installed! I have no idea why. Im using the newest internet Explorer (I think). I dont want to switch browser. Have tried reinstalling several times.

Thanks in advance!