Try This,
1
Open up RegEdit
Open up RegEdit by going to Start>Run and typing "regedit" and pressing Enter or OK. You can also enter the "regedit" command into a Command Prompt to open up the editor.
2
Locate the Office Registry Key
Microsoft stores all of the installation information for Office Products in HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office. Underneath this key you will see various version numbers, each corresponding to different versions of Office. They are as follows:
-9.0 is Office 2000
-10.0 is Office XP
-11.0 is Office 2003
-12.0 is Office 2007
-14.0 is Office 2010
3
Locate the Corresponding Registration Key
Underneath each of the version number keys you should see a "Registration" key. Depending on how many Office products you have installed (Visio, Project, etc. all will be stored underneath one of those version keys) on the machine there will be multiple
hashed keys present underneath the Registration key. Each of these hashed keys should have a value underneath it called "ProductName". You can use this value to correctly determine which hashed key is related to the product you want to remove.
4
Delete the Hashed Key
Once you have located the correct hashed registry key, delete it. As mentioned above, though, make sure you have a good backup before doing this!
5
Now, try reinstalling.