.sln file opening in Visual Web Developer 2008 Express instead of VS2010 Professional

I have Visual Web Developer Express 2008 as well as Visual Studio 2010 Professional Edition. My .sln file always kinds of opens in VS2008 Express and moreover when I right click on solution file and want to set the default program to VS2010 my "Always use the selected program for opening" is greyed out. I've tried everything but the checkbox just remains greyed out. How can I resolve this issue?

Note: For other file types like .csproj etc I am able to set the default program for opening. But for .sln file the "Always use th开发者_Python百科e selected program for opening" is just greyed out.

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You can open Visual Studio 2010 Pro go to Tools - Options - Environment - General and use Restore File Associations button. After that the sln files should open by default with VS.