error when starting half lfie 2

[final_chrono]

I just got half life 2 and i keep getting this message at the main menu when everything is still blurry

'The procedure entry point Q_vsnprintfRet could not be located in the dynamic link library vstdlib_s.dll.'

i dont have a clue what it means, but is closes half life when i click ok

thanks

 

[Beerdude26]

Sounds like some files are missing. Validate your files. Here's a shortcut for it: steam://validate/220

 

[final_chrono]

ok thanks i got past that i reinstalled steam and half lfie, but now i cant get past the opening video. When the guy is talking about you sleeping on the job it freezes and goes into a broken record like deal. i tried going to run and regedit and changed something to 18000000 or something like taht rebooted and it still doesnt work, any help will be appreciated

thanks