Since Computer Shield is still relatively new, we don’t have much information about the product. This page is still incomplete.
If Computer Shield warns you of a threat, it is best to do a quick Google search before choosing whether to delete it or bad. There is a chance it could not be a threat.
If Computer Shield warns you when open your email, it is most likely it is a virus. Nowadays, that is how threats spread. After deleting the virus, it is best to reboot the computer.
You can find more information on what Computer Shield protects you from in the Features page. HERE.