In Office 2007, the Detect & Repair feature was replaced by the Office Diagnostics Tool.
To run it, do the following:
Click the Microsoft Office Button (4 coloured boxes, upper left) > Word Options > Resources > Diagnose > Continue > Start Diagnostics.
If that should yield no result for your problem, try repairing the installation by selecting Office 2007 in the Control Panel > Add or Remove Software, then select Repair.
If the problem still persists, run Word in safe mode (winword.exe /safe). Should the button be active again, the problem maybe caused by an add-in. Deactivate one after another in order to see which one it is.
