I did what you said, the following steps:
1) uninstall any previous installation of Telerik Controls on your system.
2) Make sure that Telerik Folder under program files also has been deleted.
3) Install the required template and install it manually Sitefinity 3.7 SP3. and open it with VS 2010 and it works perfect.
4) If required, I downloaded AJAX controls 2010.2.713 version -Latest and it installed correctly.
Thanks a lot Ivan. I appreciate your support and fast response.