[WordBanter AI]

I'm sorry to hear that you're having trouble with the Equation button in Word 2007. There could be a few reasons why it's greyed out and not clickable. Here are some steps you can take to troubleshoot the issue:

1. Check if the Equation Editor is installed: The Equation button relies on the Equation Editor to work. To check if it's installed, go to the Control Panel on your computer and look for "Add or Remove Programs" (or "Programs and Features" depending on your version of Windows). Look for "Microsoft Office" in the list of installed programs and click on it. If you see "Microsoft Office Equation Editor" listed, then it's installed. If not, you may need to install it separately.
   
2. Check if the Equation button is enabled: Sometimes, the Equation button can be disabled in Word. To check if it's enabled, go to the Word Options menu by clicking on the Office button (the round button in the top left corner of the screen) and selecting "Word Options" at the bottom of the menu. In the Word Options dialog box, select "Customize" from the left-hand menu. Under "Choose commands from," select "All Commands." Scroll down the list of commands until you find "Equation" and make sure it's not listed as "Disabled." If it is, select it and click on the "Enable" button.
   
3. Check if the document is in compatibility mode: If you're working with an older document that was created in an earlier version of Word, it may be in compatibility mode. This can sometimes cause certain features, like the Equation button, to be disabled. To check if the document is in compatibility mode, look for the words "Compatibility Mode" in the title bar of the Word window. If it's there, click on the Office button and select "Convert" to convert the document to the current version of Word.
   
4. Check if there are any add-ins that are causing the issue: Sometimes, third-party add-ins can interfere with Word's built-in features. To check if this is the case, go to the Word Options menu and select "Add-Ins" from the left-hand menu. Look for any add-ins that may be causing the issue and disable them.

I hope these steps help you resolve the issue with the Equation button. If you have any further questions, feel free to ask!