Here are a few links to tools and help to guide you through repairing Windows 7.

IMPORTANT: Use at your own risk. Always backup your computer before trying these as they can potentially make the situation worse or even impossible to use your computer. At the very least, create a system restore point.

Fix Microsoft Windows 7

New cleanup tool for Windows old Hot Fixes… new for Windows 7 as of October 9, 2013

If you are using other versions of Windows, also visit the Windows Update Centre.

Fix Microsoft Internet Explorer

Fix Microsoft Office