After running any game on Steam and then closing it, no matter if it's CS:S which isnt really a demanding game or CS:GO, my PC runs extremely slowly, more or less lagging on the desktop you could say. Programs tend to freeze when they load up and take their time to open, chrome itself takes about 2 minutes, after about 5-10 minutes of my PC "lagging" it goes back to normal, has anyone had this problem before, if so suggestions on how to fix it would be great. Bare in mind the games don't lag whatsoever.
Games I've run with the lagg after closing;
mw2
mw3
css
csgo
l4d
l4d2
PC specs;
i5 3570k
GTX 560
4GB ram
msi mobo - i can get the exact model if needed
Any suggestions would be great!