I found the below information to stop dpupdchk.exe from running and eating
up 3 to 5 MBs of RAM but it doesn't apply to my version of Vista Home
Premium since there is no Local Security Policy or Software Security
Policies under Administrative Tools. How do I stop this from running?

To prevent this task from running you will actually need the assistance of
Windows itself, as follows :

a) Open Local Security Policy in Administrative Tools in the Control Panel.
b) Look for Software Security Policies.
c) Right-click Additional Rules.
d) Choose New Path Rule.
e) Click BROWSE and choose C:\Program Files\Microsoft IntelliType
Pro\dpupdchk.exe.
f) Set the Security Level to Disallowed.
g) Click OK.
h) Close "Local Security Policy".
i) Reboot your PC.
j) You're done.