Issue:
Unable to activate over the internet. "Product has been activated too many times"
Attempting to activate over the phone then also fails with "Installation ID is invalid"

Resolution:

-Step 1

Goto start, and then search or run.

If using Vista, Windows 2008, or Windows7
Type in %allusersprofile%\Microsoft\OFFICE\DATA

If using Windows XP, Windows 2003, or Windows 2000
Type in %allusersprofile%\application data\Microsoft\OFFICE\DATA

Hit enter. You will see the following files below.

Capture

(Note: If you are having this issue in Office 2003 the files will be OPA11.BAK, and OPA11.DAT)

Delete the OPA12.DAT (or OPA11.DAT if 2003) file. Then re-open an office app and attempt activation over the phone again.

This is documented in step 3 of KB919895

How to troubleshoot problems that you may experience when you try to activate a 2007 Office product
http://support.microsoft.com/kb/919895


-Step 2 (Step 2 is not always required, but sometimes is)

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:

322756 How to back up and restore the registry in Windows

Delete the registration key in the registry for the product you are having issues activating.

(Note: If you are having this issues in Office 2003 the registration key will be in 11.0. If 2007 the registration key will be in 12.0)

For this example let’s say we are having this issue with Office 2007 Enterprise.

Open the registry by Clicking on start, goto run (or start search if using Vista), type regedit and hit enter.

Browse to HKLM\software\microsoft\office\12.0\Registration\{Guid}

You may have more than one {guid} listed under the registration key. Look at the “ProductName” key on the right side to determine which guid is for the problem product. In my example we can see that the ProductName is “Microsoft Office Enterprise 2007”. So we will delete the {90120000-0030-0000-0000-00000FF1CE} Guid on the left.

Untitled

Re-launch an Office app. Like Word for example. It will prompt you to enter your product key. Enter your product key and then when you go to activate you will have a new installation ID and should be able to activate over the phone. If automated activation over the phone fails, make sure to speak to the live representative.