If you still do not have lib file then you can link at run time by using loadLibrary to get a HANDLE on the dll and then use GetProcAddress to obtain function pointer to the API you want to use.
Well, in case it's possible to link by means of GetProcAddress, it's always possible to make your own lib to link to the dll. But my impression was the question was about a bit different situation when the guy is not able to identify the dll to link to.