How to fix visual studio 'projects out of date' message each time I run it

Question

I have a visual studio (2005) solution file with 70 projects.
Each time I press F5 to run it, it tells me that 4 of the projects are out of date, and asks me if I want to re

Answer 1

I had this exact problem in VS2010 after I deleted some source files that were no longer used in my project. Simply selecting "Clean Solution" from the "Build" menu and then rebuilding the solution fixed the problem for me.