Windows Vista Windows installer opens when program opened

My son's Dell Precision M4300 laptop has Vista Ultimate SP1 and Office 2007 Professional. Whenever he opens any office document, and haphazardly when he right clicks on other programs, Windows Installer opens up and tries to reinstall the program. This is the message given:
"preparing to install, please wait while windows configures Microsoft Office Professional 2007 "
error message: Error 25004.Config.Xml not specified; A valid config.xml file must be authored when deploying '(null)'.
2nd error message: <directory of file> Fatal error during installation.

Opening up a office 2007 program or diagnostic tools gets the same error.



video icon error:
when the picture icons for videos tries to load, this window pops up:
Windows Installer
The feature you are trying to use is on a CD-ROM or other removable disk that is not available.
Insert the 'Sonic CinePlayer Decoder Pack' disk and click OK.


when cancel is pressed, the picture icons for the videos finish loading fine.

I'm not sure whether I need to have Vista or Office repair itself or reinstall the program. I figure that if it was just Office, then the other problems wouldn't appear. What suggestions might you have?

 

I opened a Word document with Office 2007 CD in the laptop. Windows installer came up with the same message and didn't fix anything. I restarted the computer with the Dell reinstall Vista DVD in it, and the repair function didn't seem to offer any option to address this problem. Any other suggestions or guidance anyone might have?

 

Apparently, this was two separate problems. The first problem was fixed by uninstalling Office 2007 using these steps (http://support.microsoft.com/kb/928218/) and then reinstalling Office 2007. The second problem was caused by Roxio Creator. The problem can either be eliminated by deleting or renaming the Sonic CinePlayer folder. All is working fine now.