JB,
That's a simple one. Follow my instructions exactly and ask if you do not understand. You will be modifying the ini file of Avast.
Right click on My computer and click explore.
Navigate down to C:\Programs\Alwil software\Avast folder.
Inside you will see the Data folder. Click on the DATA folder to open.
NOW....look for Avast4 or Avast.ini file.
If you are unsure, right click on the name, then Properties.
It will show you if it has the .ini ending
Once you have identified the Avast.ini file, scroll down the file until you see the line "Show Help Checklist=1". It usually appears towards the bottom of the list under the [Simple] heading. Change the 1 to a 0.
When the program asks if you want to save the changes, answer YES.
That's it. Restart Avast and the window will pop back up.
You really don't need the window, but you can view it until you feel comfortable with Avast.
Good Luck.