Your best bet: Make a backup of everything, and install slackware 3.1 or
something new. It would a major pain in the dumper to upgrade everything
A better bet would be to install a distribution which allows painless
upgrades without requring that you do a backup and re-install from
scratch. Examples of such distributions include the RedHat and Debian
distributions. As a bonus, such distributions usually pay more
attention towards fixing security bugs (and bugs in general), and allow
you to easily download an upgrade package which will fix the one or two
programs which are broken (again without requiring a reinstall from
scratch).
At this point, I can't really recommend that anyone use Slackware, when
there are far better choices available.
- Ted