Moved provisionally to VirusScan 13.
Double-click the taskbar icon to open SecurityCenter
Click Advanced Menu (bottom)
Click Configure (left)
Click Computer & Files (top left)
Click Advanced (right)
Click Scheduled Scan (left)
Uncheck Enable Scheduled Scan as per the picture below (click to enlarge).
Click Apply and OK.
This was from 2009 and the software used then has long since been obsolete. I suggest you start a new discussion in VirusScan and give more details such as your software version (open it and click 'About'), operating system and service pack etc. etc.