If you're using Windows XP open the following folder in Windows Explorer:
C:\Documents and Settings\All Users\Start Menu\Programs\Startup
Create a new shortcut in that folder with the following parameters:
"C:\Program Files\CCleaner\ccleaner.exe" /AUTO
Name the shortcut whatever you wish, a good name would be:
CCleaner
Now when each user starts their user profile CCleaner will automatically clean junk files. Note: The Issues scanner won't be executed automatically, it has to be executed manually in order to remove issues from the registry.