Not knowing what products you have doesn't help us, but if you have Spamkiller for instance (Anti-Spam) make sure that your email inbox isn't used for storing emails. Otherwise the very first thing it does is scan them, as does VirusScan now that I think about it.
You could turn off the auto Quickclean and Defragmenter .
Double-click the taskbar icon to open Security Center
Click Advanced Menu (Bottom left)
Click Tools (left)
Click Task Scheduler (far left)
Delete both those tasks if you wish.
But don't forget to do a periodic system cleanup via Control Panel/System & Maintenance.
Whilst in there you could set Security Center to notify you when updates are available rather than just install them whenever they are ready.
Click Configure (left)
With Security Center highlighted at the top left
Click Advanced (right)
Click Update Options at the left.