I've been hanging out in the forums over at http://forums.iis.net. A person was having an issue where a 3rd party product potentially was causing an issue. You can use Process Explorer from Sysinternals. If you know which service the DLL is potentially loaded, you can use tasklist /M /FI "Services eq inetinfo". This shows what files are associated with that process. I thought I'd pass this along.
Image Name PID Modules
========================= ======== ============================================
inetinfo.exe 676 ntdll.dll, kernel32.dll, ADVAPI32.dll,
RPCRT4.dll, msvcrt.dll, IISUTIL.dll,
USER32.dll, GDI32.dll, ole32.dll,
CRYPT32.dll, MSASN1.dll, USERENV.dll,
Secur32.dll, WS2_32.dll, NSI.dll,
IMM32.DLL, MSCTF.dll, LPK.DLL, USP10.dll,
rpcref.dll, IisRTL.DLL, iisadmin.dll,
COADMIN.dll, OLEAUT32.dll, PSAPI.DLL,
AUTHZ.dll, ADMWPROX.dll, IISCFG.DLL,
ATL.DLL, abocomp.dll, HTTPAPI.dll,
WSOCK32.dll, nativerd.dll, XmlLite.dll,
IISRES.DLL, NTMARTA.DLL, WLDAP32.dll,
SAMLIB.dll, CLBCatQ.DLL, metadata.dll,
MPR.dll, msxml3.dll, SHLWAPI.dll,
comctl32.dll, rsaenh.dll, SHELL32.dll,
mlang.dll, rsca.dll, svcext.dll, wamreg.dll
Pondering Thought 