I want to drag and drop MapControl into a design view, but I have an error: System.Runtime.InteropeServices.COMException(0x80040154):Classe non enregistrée (Exception from HRESULT:80040154(REGDB_E_CLASSNOTREG)). I find that your map control is not registered or Class not registered, but I don't know how to do it in VS 2008 SDK 9.3, please help.
Try "repairing" your ArcGIS SDK...goto Add/Remove Programs and try to repair the installation.
This should replace all the erroneous entries and re-register the libraries and you should be just fine.
Check your com libraries. It could be they are not registered and the .net hooks into them are not able to instantiate them. This is just a guess though.