Your mother is one smart woman... I have no idea what we have broken. Have you tried to remove the old installation, clean the GAC and if this does not help could you try to move away the design dlls from the installation folder. Don't delete them just move them to your desktop for example, close and open the studio and if this does not fix your problem move them back.
Does it brake in design time only? In other words - does it build and work in runtime? I don't think it has something to do with the OS and VS it looks more like a version mismatch between the dlls.
the Telerik team
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