Reinstall Steam

Right i have been creating a game using Source SDK for a uni project but recently i have done something that has made Source SDK crash when ever i open or create a new map, i have reinstalled the Source SDK and reset the configuation neither of which worked so i may have to reinstall in the hope that that will fix the error, but i have 12 games and 3 SDK's installed and i dont want to have to redownload and reinstall all of them, is there a way to reinstall Steam without having to reinstall EVERYTHING?

also if you have any ideas on why Source SDK keeps crashing when i open or create a new map please tell me i have been looking everywhere but i have found nothing

 

Sorry have no idea about the crash, sometimes they are quite random for Steam. Back up whatever folder that you don't want to get uninstall in the process, say your game's folder and reinstall Steam.

 

I cant tell you why the Source SDK is crashing but I can tell is that I have copied my steam folder to an external HD, reformatted and installed the OS.
Copy pasted the steam folder, click the exec file that is steam and it will tell you that you need to have steam installed. Click yes and done

 

is there a special tool or something that i need to use? or can i just copy the folder my self?

 

No, just cut and paste your folder out of the Steam directory and proceed with the uninstall. After you reinstall Steam, cut and paste your folder again back into the directory.

 

so what folder is it that i have to cut or do i just cut the ones i want and do a complete reinstall of all the SDK content?
because in steamapps it has my username folder which has all the games and SDK but it also have loads of weird files with blue icons like Halflife 2 deathmatch (game cache file) and Left 4 Dead base (No Cache File) what do i do with all of these, cut them as well or is it just my folder with the games that i want?

 

You need to backup them as well else you'll still need to do some downloading after you reinstall your Steam. Basically, backup your "steamapps" folder. Not sure about the SDK as I have no experience with them.

 

Try resetting Hammers config file. That may stop the crashing...