Hi Wendy Hunt,
As I understand, you upgraded RadControls successfully, but your project won't compile any more. If am right, following this steps should solve the problem:
1) Close the Visual Studio.
2) Stop the IIS if the site is deployed on it.
3) Close all other programs that eventually use “bin\Telerik.Web.UI.xml”
These 3 steps are to ensure no one is locking the file for writing.
4) Check the security of “bin\Telerik.Web.UI.xml”, to make sure you have write permissions.
5) Now copy “Program Files\Telerik\RadControls for ASP.NET AJAX Q2 2010\Bin35\Telerik.Web.UI.xml” to the “\bin” folder of your project.
About your second question, there is no need of removing the old versions of RadControls. You can use different versions for different projects. Just be sure to assign the right one in the references of the projects.
If you have any more questions, let us know.
All the best,
the Telerik team
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