pthreads win32 lib problem

[qweqweqwe]

I have some project that uses pthreads.dll and works perfect with it.
I am trying to change it to use static pthreads.lib it compiles fine but when i run the .exe file i get

this application has failed to start because posix.dll not found .
 i use vc++

can someone help me how to make my project start using .lib

thanks alot