Scan Last run: today - How when PC off all & unplugged

Hi all, this is my first post so please be gentle.

 

A few minutes ago when I turned on my computer for the first time today the display showed a Quick and Full Scan both completed today, 2/12/2011.  How can that be possible when neither my ISP or computer were running?

 

I've had several issues with my laptop since I bought it.  I thought Norton would give me some peace of mind.  Complete system restore completed with initial Norton installation - had to use disks and everything.  I've had to re-download Norton twice.  The most recent time was a couple of weeks ago.  Now the first thing I do when I start the system is run a Live Update.  Lately, last few days, there is "nothing" found - not even a tracking cookie.  Should I re-download daily?  What gives?  It seems Norton starts and stops at the drop of a hat.  How can I be certain "System Status Secure" is just that - secure?

 

If anyone else has had a PC be off and ALL components unplugged all day only to turn it on and within seconds have a report of scans completed within those few seconds please contact me so I'll know I'm not alone.