Why is unity stuck at installing?

Why is unity web player stuck and only showing this in the details.

Execute: C:\Users\Vultareas\AppData\Local\Unity\WebPlayer\Uninstall.exe /S /CurrentUser _?=C:\Users\Vultareas\AppData\LocalLow\Unity\WebPlayer

I have tried to turn of all things using a web browser and I have even let it be for hours nothing happens. please help me really want it to work so I can play a game on firefox.

Also I'm using windows 7 if that should affect in any special way.