How do I re-install proofing tools for Word 2007?

That indicates a serious problem in the current installation, so the original suggestion to "uninstall and reinstall" the proofing tools is correct.

Do steps 1 to 4 of the previous procedure. Instead of step 5, click the Add or Remove Features option and click Continue.

The next page shows a list of the parts of Office. Click the plus-sign-in-square next to "Office Shared Features" to expand it. Click the Proofing Tools box and choose Not Available from the menu. Click the Continue button and wait for the program to finish. Again, it's a good idea to reboot at this point.

Now do the whole thing again, except that after clicking the Proofing Tools box, you choose Run From My Computer from the menu. That will reinstall the tools (and may ask for the disc). There's no need to reboot at the end of this part.

1. Close Word.
2. In the search box on the Windows Start menu, type Programs and Features. When that item appears at the top of the Start menu, click it.
3. In the Programs and Features dialog, locate "Microsoft Office 2007" in the list and click on it. (It may mention the edition, such as "Standard" or "Professional".)
4. In the menu bar at the top of the list, click the Change button.
5. When the next dialog finishes initializing, click the option for "Repair" and click the Continue button.
6. The repair may or may not ask you to insert the disc -- that depends on whether a copy of the installation files was saved to your hard drive during the first installation and not removed later.
7. When the repair finishes (which may take 10 minutes or more), it probably isn't necessary to reboot the computer but it's often a good idea. If the disc is in the drive, remove it first.