I'm attempting to get a better understanding of parasite removal procedures.

I have seen the following terms used
- End running tasks
- Unregister DLLs
- Clean Registry entries

I think I understand what ending a process and Clean Registry entries means but I have not been able to get an explanation of what Unregister means.

Can any one give a pointer to or an explanation please.
(I'm an old hardware engineer so this software stuff is not my cup of tea)

Thanks,
-p-