How to Change the WordPress AdSense Banner

1. Log in to your Google AdSense account. Click the 'My Ads' tab and click 'Get code' under the new AdSense unit you want to use. Right-click with your mouse and click 'Copy.' Log out of AdSense.
2. Log in to your WordPress administrative account.

3. Click the arrow next to 'Appearance' to collapse the Appearance menu. Select 'Widgets.'
4. Click the sidebar or footer containing the widget for the AdSense banner you want to change. Depending on your current WordPress theme, a single sidebar or multiple sidebar or footer areas may appear in your blog. Clicking a sidebar or footer will display its widgets.
5. Click the arrow on the widget that contains the AdSense banner code. This widget should be a 'Text' widget that lets you add custom text or code. The widget will open to display its code.
6. Right-click the code with your mouse. Click 'Select All' and then click 'Paste' to overwrite the code with the new AdSense code you copied earlier. If you want to make sure all of the old code is removed, click 'Delete' before you paste the new content.