This image is a screenshot of my version of AIM (22.214.171.124). As you can see the ad is gone! I also just painted over my screen name above the "Enter status message here..." text box. It's not a side effect of the Instructable. Enjoy!
Step 1: Close out AIM
Step 2: Editing the first file.
"your_version" is your current version of AIM, not the name of a folder =)
hit CTRL + F and search for "adcontainer" and change "collapsed=false" to "collapsed=true" .
Save the file.
Step 3: Editing the second file.
remember the note from the previous step about "your_version"
hit CTRL + F and search for "AimAdRotateInterval"
Change the values that are there for these four lines to zeros so they look like this"
Save the file, exit Notepad... start AIM.. and enjoy your ad-less buddy list!