How to stop a .dll process so it can be deleted

I recently obtained what my system sees as a virus. It is jkkjkjk.dll. I have searched and tried everything possible to try and remove it, but to no avail. When I try to delete it, my system says that it is in use and access is denied. My question is … How do I stop a running .dll process so that I can delete it and hopefully rid myself of this problem?