Go to start > Run > Type:
Then click SATARTUP up at the top.
Remove all ticks.
Restart the computer and if the message does not appear then it is on of the programs that you have set to run when windows loads.
Place a tick back in the box in the startup list ONE BY ONE and restart each time. This should tell you which program is causing the message.
I have afeeling it is norton utils.
For a list of what you are stopping from starting (in msconfig) click here
If you are running Firewall and AV, ideally you will have these to start auto. As your only seeing whhat program is cauing the message, you'll be ok to stop these programs.
Assuming it one of the programs that is set to start when windows loads. Which the above will tell you.