Games start lagging for no reason whatsoever

[Arashikage]

So I've been playing a lot of Euro Truck Simulator.  However, just last night I alt tabbed out of the game which was playing just fine with no lag, and when I got back in I was hit with immense lag.  It made my game unplayable.  I had to turn off my computer anyway, so I switched to my laptop for the night.  When I got back downstairs this morning, I decided to play some more Euro Truck Simulator, but it kept lagging the same way.  So I did the only logical thing; I played another game.  At least, I tried to play another game.  Every single game I play lags like there's no tomorrow.  I've tried clearing up hard drive space, I've tried using CCleaner, I've tried cleaning my registry, ending unnecessary tasks, even checking to see if everything was still functioning properly.  My computer says everything is fine, but clearly something is wrong.  

 

My specs:

 

If someone could help me I'd be very appreciative.

[DZComposer]

It could be a bug with the game if it is just that one game. If it is every game you play, next culprit would be the video drivers.

I know until it was fixed in an update TF2 absolutely HATED alt+tab. It would actually crash if you did it.

[Fana McCloud]

Have you done virus and adware/spyware scans since it started happening to make sure everything's okay on that front? Is there a virus scan or some other resource intensive process in the background that could be slowing things down? (Check with task manager if you can.) 

[Arashikage]

There's no scan going on, and while I doubt it's a virus seeing as how they started lagging as soon as I went back into the previously minimized game, I can still run a scan right now to see.

 

EDIT: I updated my graphics drivers and it seemed to have fixed the problem.  Thanks for the support.

[Fana McCloud]

You never know sometimes - if you did any web browsing in the time you tabbed out you could've gotten a virus whose effects are only really pronounced in intensive applications (like games). Good to know you fixed it though. XD

[Arashikage]

Yeah it was my drivers, I updated them and now my games work.  It was a problem with all the games lagging, but now it's fixed.