There is no RegClean.Exe for XP.
You said "it worked good"!
In fact it didn't do very much, the program was designed to cleanup the
Registry after (Visual Basic) programmers had done a trial install of
their homemade program before trying another installation.
Below is what MS said about RegClean at the time:
<QUOTE>
What RegClean Does
------------------
RegClean analyzes Windows Registry keys that are stored in HKEY_CLASSES_ROOT
in the Windows Registry.
It finds keys that contain erroneous values, and after recording those
entries in an Undo.reg file, it removes them from the Windows Registry.
What RegClean Does Not Do
-------------------------
RegClean does not fix every known problem with the registry.
It does not fix a "corrupt" registry; it is limited to fixing problems
with normal Windows
Registry entries located in HKEY_CLASSES_ROOT.
It is very possible that RegClean will not correct a problem that you
have encountered.
RegClean will leave any entries in the registry that it does not
understand or that could possibly be correct.
</QUOTE>