When i installed avast it gave me the option to do a boot up scan.now i want to do one again. How do i do the boot up scan?
[]Right-click on the avast icon
[]click start avast Antivirus
[]after avast scans memory (or you can stop it)
[]click the menu for pull-down
[*]click 'schedule boot-time scan[/li]
Then reboot you computer and avast should scan your PC.
Which is your Windows? 32 or 64 bits?
Boot time scanning is only available in 2k/XP/Vista 32 bits.
xp pro. Thanks now i know how to do a boot up scan.
Your welcome! Living and learning 
And Avast! is our greatest friend in the world ;D ;D