Garry's mod crashing,tf2,css

So i think this started at 7.9 and umm i had garrys mod dedicated server and it did work fine for like 2 months but now its not working so i deleted it.
After that i did go to garry’s mod, tried making multiplayer server via garry’s mod (it have worked well until 7.9) and when i make it it says that hl2.exe has stopped working.
this happens to tf2,css too and i have tried to reinstall garrysmod but it doesn’t work it does the same thing please help me ;____; i had data execution prevention or whatever its called it was enabled and after that i disabled it but it doesnt fix the problem. AND sorry for my poor english i did write this fast

For GMod

http://forum.facepunch.com/showthread.php?t=1211472

I have no idea why CS:S and TF2 keeps crashing for you, it works fine with me.