I am working on some C# projects with Visual Studio 2005, and I am trying to change the platform target from x86 to Any CPU. I already went through all the dependencies that
Make sure you've changed both the Configuration Platform and the Platform Target to Any CPU. If all else fails you can open up the .csproj and manually change the references. Right click on the Project, goto Unload Project. Then right click and goto Edit MyProject.csproj. The properties for the project may still include the default Platform as x86:
Debug
x86
Also consider the case where the Solution still has the x86 configuration in Configuration Manager. I've found for some complex Solutions with multiple projects that have different configurations I have to spend a lot of time in Configuration Manager getting everything straight.