A. Windows NT has problems with "DLL Hell" where many applications may replace core DLL's which may cause incompatibilities between applications.
Windows 2000 takes steps to elevate the problem by protecting core DLL's from being replaced but in the mean time there are a number of sites that help to track DLL versions etc:
- File Version Information Center from Microsoft - http://support.microsoft.com/servicedesks/fileversion/default.asp?vartarget=msdn
- Datent Files Database - http://www.datent.com/resourcedb