Did you remember to restart your computer between uninstalling and reinstalling? (You often need to do that to clear the old registry entries completely).
Try uninstalling with Microsoft EasyFix:
Click the relevant blue 'Download' button in Section 2 here:
https://support.microsoft.com/en-gb/kb/928218
Download the file to any convenient location on your hard drive.
Double-click on it to run it.
Afterwards, RESTART YOUR COMPUTER.
Reinstall Office 2007.
Alternatively, simply ditch Microsoft Office altogether and use OpenOffice (which is what most people around here, including me, do anyway):
https://www.openoffice.org/
(If you choose to do so, I strongly recommend changing the default 'Save' formats to Microsoft ones:
http://helpdeskgeek.com/office-tips/set-openof%EF%AC%81ce-org-to-save-in-microsoft-of%EF%AC%81ce-format-by-default/ )