Can you email me a screen shot at RodStephens@CSharpHelper.com
Be sure you unzip the project somewhere you have read and write permission. Visual Studio can't manage the project unless it can write more files into the same area.
Can you use the File > Open Project menu command to open the .sln file?
Can you open the .csproj file? (That's the project file. The solution could contain more than the solution file but unless you're working on multiple projects in one solution this would be okay.)
The only other thing I can think of is that a file downloaded from the internet should be marked as from the internet zone. When you try to unzip it, it should ask if you want to trust the file. Does it do that?
Sorry I can't figure out what's wrong. I haven't seen this problem before and can't find any posts on it.