BUG: Windows Installer popping up periodically while using MSDN 19 April 2005 at 00:00
If you get the windows installer popping up periodically when using Visual Studio then this note is for you (specifically if it happens when you are using MSDN help). The following article has a solution for this:

http://www.eggheadcafe.com/ng/microsoft.public.vstudio.setup/post272771.asp

You need to re-create the problem and check your application event log to see that the events generated by the windows installer matches the events described in the above article. If so you can apply the fixes described. If you get it in other situations then again the application event log is a useful starting point in troubleshooting.

The problems are essentially being caused by conflicts between Office 2000 and Visual Studio.