dot net 3.5 app to run on IIS7.5

Hi I have an application which has a main project set to ver 3.5 with some utility projects set to ver 2.0. I need to migrate the app to work on IIS7.5. I have tried re开发者_开发知识库compiling the app as is and putting it on the server but to no avail. What do I need to do to get this app running on 7.5? Will I need to upgrade the projects in the solution to .net 4.0?

any pointers much appreciated.

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No you don't necessary need to upgrade to .NET 4.0 even if it could be nice :-) All you need is to make sure the application pool is set to use CLR 2.0 in IIS and it will run just fine (obviously .NET 3.5 needs to be installed on the server).