Show message (or completely different page) for users that haven't logged in for a while

Hi,

we have a site where several users haven't logged in for a long time. We're trying to get some of them to start using the site again, but the website itself has gone through a lot of changes. is there any module that allows us to show a message to new users or users that haven't logged in for a while? Or if possible, a completely different page showing what's new in the site, perhaps a walkthrough the site of some sort?