The information about a registered component is written to the registry. You can either enumerate the HKEY_CLASSES_ROOT/CLSID keys and check for the ProgID, or if this is your own component created in VB then it is also created as HKEY_CLASSES_ROOT/ProjectName.ClassName, under which a ClsID key exists, if the default value for that key is also contained under the HKEY_CLASSES_ROOT/CLSID key then the component is registered.