A couple of ways to do it. Process explorer should tell you what exactlyt has what resources open, using which dll's, which memory blocks, etc:
http://technet.microsoft.com/en-us/sysinternals/bb896653
If that doesn't do the trick, Dependancy walker should. http://www.dependencywalker.com/
If you need more depth than either of those can provide, there are some other "advanced class" tools out there too.
Edited, Dec 22nd 2011 6:45pm by Kaolian