just check out what does WaitForSingleObject returns, it could be any of the follwing:-

If the function fails, the return value is WAIT_FAILED. To get extended error information, call GetLastError.

The return value on success is one of the following values:
WAIT_ABANDONED
The specified object is a mutex object that was not released by the thread that owned the mutex object before the owning thread terminated. Ownership of the mutex object is granted to the calling thread, and the mutex is set to nonsignaled.

WAIT_OBJECT_0
The state of the specified object is signaled.

WAIT_TIMEOUT
The time-out interval elapsed, and the object’s state is nonsignaled.