A. If when trying to add a counter and the list of objects and counters is incomplete or blank the problem could be the data files that hold the list has become corrupted.
Under registry key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Perflib is a key identifying the language of the system, e.g. 009 for U.S. English. Performance monitor will only list that counters for the selected language ID (this can be changed via control panel)
To resolve the problem restore the files PERFC<country code>.DAT and PERFH<country code>.DAT (e.g. perfc009.dat and perfh009.dat for U.S. English) from the installation CD to the %systemroot%\system32 directory