Trying to figure out in which process a particular DLL is currently loaded, I have found two solutions (perhaps there are more).
Solution 1: tasklist.exe
tasklist /m <modulename>.dll
Solution 2: listdlls.exe (from sysinternals)
listdlls -d <modulename>.dll
It might be that listdlls is more reliable than tasklist. I have ran into cases when tasklist failed to list processes that had a specific dll loaded, while listdlls was showing them.