Turn off Disk Cleanup

[Kevin]

Hello - I have three hard disks, one for my system and
program files and two of which are full of multimedia
files. I am constantly recieving the message from windows
(about every 10 minutes) to activate the disk cleanup
utility for these two disks which are nearly 100% full.
How do I turn this off?

I KNOW I've seen this before (and probably turned it on
myself!) but I can't find it now after much searching.

Thanks!

- Kevin