Steam Engine Error

For the last week or so everytime i've started Counterstrike source or Half life 2 (currently only have those two installed) it quits to desktop and i get "Module could not be initilised) and a second window with an error code, i've tried reinstalling hl2/css, i've tried uninstalling steam and hl2/css, i've even tried reinstalling my whole OS, so far i've managed to fix the error for one time, the next time i goto play its back, just wondering if theres anyone here who knows how to fix this because i dont particularily want to have to download the whole thing again everytime i want to play it.

 

Does the error specify what module is failing? Can you tell what the game is trying call when the crash happens (IE - a certain level, sound, model)?

 

its just trying to open the game, as soon as the progress bar for connecting to a server opens it exits to desktop the code given after the error box (doesn't say which module failed to load unfortunately) is


"the instruction at 0x10d53w2c referenced memory at 0x0ec7a1a0 which could not be read"