I recently got the Oblivion digital deluxe edition on steam and it was working fine until I alt-tabbed (big mistake) out of it to print something

Now, whenever I launch Oblivion from any place (steam, desktop shortcut, Oblivion mod manager, in file application) the start up screen appears as normal BUT when I click "play", The window for Oblivion does not appear. The sound works fine and I can even click on menu buttons if I randomly click but It still looks like I'm on my desktop. Is my graphics card (for some reason) not rendering Oblivion after alt tabbing it to print?

Note: I'm using Windows 7 with a NVIDIA Geforce 9600 GT as a graphics card