You receive an Invalid Product Key error when trying to install Access 2010 onto a machine that already has an Office 2010 suite installed.
The originally installed Microsoft Office 2010 suite may have included a trial version of the Microsoft Office 2010 Professional suite, which includes Microsoft Access 2010. If you attempt to upgrade the trial version of the Microsoft Office 2010 Professional Suite by entering a product key for a stand-alone copy of Microsoft Access 2010 as the upgrade key, the upgrade fails because a product key for the Microsoft Office 2010 Professional suite is required. A product key for an individual program within the Office 2010 Suite, such as Access, cannot upgrade the whole suite of programs in Office 2010 Professional nor can it upgrade one individual program from the suite, such as Access.
In order to install Access 2010, you will need to first remove the trial application from the machine. After doing this, you will then need to install Access 2010 from the standalone Access 2010 media, which would either be an Access 2010 DVD or the Access 2010 downloaded media.
To remove the Access 2010 trial:
1. Close any Office 2010 applications that are open.
2. Choose the Add / Remove program option on Windows XP or the Uninstall a Program option on Windows Vista / Windows 7. This can be done through the control panel or by typing appwiz.cpl into a run command line from the Start menu.
3. Locate the previously installed Microsoft Office 2010 suite in the list of programs. The most common suites with a trial would be Office Home and Student 2010 or Office Home and Business 2010.
4. Select the Microsoft Office 2010 suite and then right click on it and choose Change.
5. In the Change dialog, select the Add or Remove Features option and then click on Continue.
6. Within the Installation Options dialog, click the black down arrow next to Microsoft Access and choose Not Available.
7. Click Continue.
8. Once the configuration process completes, click the Close button.
Note: After going through these steps if you would like to completely remove the other Office 2010 trial applications from the machine, you can do so by going through the first set of steps in the following article: Remove or uninstall Office 2010 Trial
To install Access 2010:
1. Locate the Access 2010 DVD or download the Access 2010 media from the site it was purchased from. If you do not have the media, you can download it by going through the steps in: Get a backup of Office 2010
2. Insert the Access 2010 DVD into the DVD ROM drive or double click on the downloaded media.
3. When prompted for a product key, type in the Access 2010 product key.
4. Complete the install process.
The following KB article provides additional situations where you may encounter an invalid product key error.
836178 Invalid product key errors in Microsoft Office
for other considerations.