Entity Framework not loading in Windows 7

I had to get a n开发者_JAVA百科ew machine recently. It is Windows 7, loaded with Studio 2008, with Framework 3.5 sp1. When I load pre-existing projects that use the Entity Framework, the projects don't recognize the .edmx files. Any ideas?

I'm fully patched and running as administrator doesn't make a difference.

Opening as XML and saving I have managed to get the error " Cannot find the custom tool 'EntityModelCodeGenerator' on this system." But I have all the updates and don't see any way to add this.

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Per LukLed and his link -- This requires VS2008 SP1.