Mass forum password/reset notification?

[Life Revived]

Basically I just want to be able to make it where when a user logs in it requests that they change their password saying it as expired. I would use the expiry password option to the usergroup but if I set it to 7 days it won't matter to the people that don't login before that time. And if I have to enable it again the users that already reset their password will have to do it again and get annoyed.

Now the even better situation is if I can run something to be able to change everybody's password manually and then just send them an email explaining they need to change their passwords and I will include a link where they enter their email in and they can change it with that. Or if they try to login eventually with their old password it states that it has been changed and they need to do a reset with their email.

Any help with this would be appreciated. Thanks!