With Microsoft Office 2010 around the corner, you might at some point of time, contemplate uninstalling Microsoft Office 2007. But if you find that your Office 2007 just wont uninstall, try these:
1. First, try to remove Office 2007 through the Control Panel > Programs and Features > Uninstall applet.
2. In case it doesnt work out for you, you may want to try uninstalling Office 2007 manually with the help of KB928218.
3. If all fails, try this utility I came across here. Its aptly called RipOutOffice2007.

RipOutOffice2007 is a 3rd party freeware tool to completely uninstall & remove Office 2007 from your PC, when the standard uninstall process fails.
UPDATE: It appears from the comments that this tool does not work in Windows 7 properly. You might want to check out this Fix It from Microsoft to uninstall Office Suites.
If you have liked this post, you might want to check out some more, on topics like Office, Uninstall.