You should remove your component manually, that is...
[name].component.ts
[name].component.html // if you've used templateUrl in your component
[name].component.spec.ts // if you've created test file
[name].component.[css or scss] // if you've used styleUrls in your component
If you have all that files in a folder, delete the folder directly.
Then you need to go to the module which use that component and delete
import { [component_name] } from ...
and the component on the declarations array
That's all. Hope that helps