Hi Christine,
You may try these steps and check if that helps.
Method 1: Run System File Checker (SFC) scan to fix any corrupt system files. To do this, follow the steps mentioned in the link below:
How to use the System File Checker tool to troubleshoot missing or corrupted system files on Windows Vista or on Windows 7
http://support.microsoft.com/kb/929833
Method 2: Make sure “Windows Modules Installer” Service is started. To do this, follow these steps:
a) Click on Start-Run, type services.msc, the click on OK.
b) When the Services window loads, navigate to the **“**Windows Modules Installer “ service, the double click on it to open it.
c) Make sure the "Startup Type" says "Automatic" and started. If it doesn't, use the drop down menu to change it.
Method 3: You may follow the steps mentioned in the article below which addresses similar issue
You cannot install some updates or programs
http://support.microsoft.com/kb/822798
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:
How to back up and restore the registry in Windowshttp://support.microsoft.com/kb/322756/
Please keep us posted.