First, please make sure that you use the right product key to install the Office software.
If the key is right, this issue may occur when the previous Office software is not completely uninstalled.
First, please go to Start > Control Panel > Programs and Features (Add/Remove Program Files), Locate the Office program and uninstall it.
Then, you can try to manually uninstall Office by the steps below:
1. Download and install the Windows Installer Cleanup Utility.
2. After you install the Windows Installer CleanUp Utility, click Start -> All Programs -> Windows Install Clean Up.
3. Highlight Microsoft Office entry in the list and then click Remove. Quit the Utility.
Note: If you have got any other old or redundant office entries such as Office 2007 or other Office standalone products, such as Visio in the list, please remove them together.
4. Close all applications.
5. Click the “Start” peal, in the Search box, type "regedit" (without the quotation marks) and press Enter.
Note: If you are using Windows XP, click Start -> Run, type "regedit" (without the quotation marks) and press Enter.
6. Expand the registry tree on the left pane and locate the following two registry subkeys:
7. Right-click on this registry subkey and click Delete to delete those keys.
8. Open Windows Explorer, and then browse to the "C:\Program Files" folder
If it exists, rename the "Microsoft Office" to "Microsoft Office OLD"
If it exists, rename "OfficeUpdate" to "OfficeUpdateOLD"
If it exists, rename "OfficeUpdate14" to "OfficeUpdate14OLD"
9. Click Start, in the Search box, type "%Temp%" (without the quotation marks) and press Enter.
Note: If you are using Windows XP, click Start -> Run, type "%Temp%" (without the quotation marks) and press Enter.
10. Empty the Temp folder.
Note: If some files can't be deleted, please skip them, which don't influence the result of the troubleshooting.
11. Empty the Recycle Bin.
12. Restart your computer.
13. Try to reinstall Office 2010 again.
Please take your time to try the suggestions and let me know the results at your earliest convenience. If anything is unclear or if there is anything I can do for you, please feel free to let me know.
- Marked as answer by Sally Tang Wednesday, June 02, 2010 1:31 AM