I was just wondering how I can back-up all the information I downloaded over steam?
ie. if I where to re-format - how could I re-instal CS:S and keep my files without having to re-download the lot from the start?
Those are where all your gcf (game cache files) are located. They contain all the info that you have downloaded from steam. Copy all of them to dvdr . Hope you have a dvdr because mine equal 5.6 gigs. I like to use 2 dvdrw so that way everytime there is a new patch out for the game, I just burn all the new info back onto the dvdrw that way I don't waste dvdr's and when I reformat I have all the newest patches. Once you reformat. Download install steam again. Exit out of steam and add all the gcf back into the folder above and restart steam. All your games should be close to 100% if not 100%. Make sure to also copy all your cfg files so that you don't have to re-do all your keys and bindings over again. Hope this helps.