Hi Pete,
(1) Double click on the Diskeeper 2008 icon on the desktop (or the
start menu) and launch the Diskeeper GUI.
(2) Right click on the relevant drive in the Computer section that
lists all the disk volumes.
(3) Select 'Automatic Defragmentation' and a new window will pop up.
(4) Uncheck 'Enable Automatic Defragmentation on the selected volumes',
then click on 'Apply' and close the window.
You can also do this via the 'Volume properties' option in the quick
launch panel on the left side of the GUI. (Page. 22, Diskeeper 2008
manual).
You can also schedule automatic defragmentation for specific periods
based on a weekly pattern or specific dates (P.23, Diskeeper 2008
manual).
Finally, you can also see the resource consumption as well as the file
currently processed by Diskeeper in the Dashboard tab.
If you notice disk activity even while Diskeeper is not processing any
file, then it may be attributed to Vista's Superfetch, Indexing or
pagefile activity. I suspect this may be why the HDD activity seems
'excessive'.
Best regards