Ok, these problems with the computer are not related to the emails, it was computer performance.
The emails from the "FBI" Are fake emails, you will get these on any email account within any email system.
This you cannot stop, you just need to delete the emails (the police are aware of all these scams).
I would be happy to go through your computer and check out what the issue is and have made a request of additional service to do this for you, but changing email addresses will not solve this issue as this is not related Mike.
It appears your computer has corruption issues and this needs to be dealt by repairing it.
I can do this for you, and have made a request via Additional Services. This is optional, and if you choose to do this, I can, with your permission, remote into your computer while you watch and do all these steps (and deal with any problems that arise during them) for you. Or if you do not choose to take this service, we can continue here. This is no problem at all. Just let me know please.