At the moment we're trying to run all the main office components for Office
XP and Office 2007 on the same PC, so that users can decide which version
they'd like to run if required.  

Thanks to Bob Buckland's registry information, I've got Word XP and Word
2007 to work together without each application having to register itself
every time it runs.
However, there seems no easy way to fix this for Access.  

What I've found out so far is that Access XP sets up a registry key called
NoRepairNeeded in HKLM/Software/Microsoft/Office/10.0/Access/, and when you
run Access 2007, this key is deleted.  If after you run Access 2007, you
manually put the key back and run Access XP, Access XP doesn't need to
re-register.

However this doesn't solve the issue where if you then run 2007, it comes up
with the "configuring.." screens for quite a while before Access starts,
which as you can imagine is frustrating and annoying from a user point of
view.

The same registry key exists for Access 2007 but it seems to be ignored!

Office XP and Office 2007 are both Enterprise editions and they were
installed to their default "bin" folders, with Word, Excel, Powerpoint and
Access as a full install to my computer.  The PC is running Windows XP SP2.

Any ideas?