Is there a site where I can get old versions of software such as MSN Messenger 5.x?

The current version of MSN Messenger is 6.x, but for various
reasons, you really prefer 5.x. Can you get 5.x? Maybe. Can you
use 5.x? Maybe not. And how about other software, are older
versions available?

Maybe. Noticing a trend?

First, here’s a resource: OldVersion.com. This site maintains an
archive of old versions of a number of software packages
including MSN Messenger.

Now, we’ve determined that MSN Messenger 5 can be found but will
it work? Probably not. The MSN Messenger service currently
requires version 6.1 or better. If you run an older version it
should prompt you to update to the current version.

This brings up a bigger topic with respect to old versions of
software – they may no longer work. Messenger is a classic case
because it communicates with a backend service that enforces the
version. Other old versions of software, even standalone
packages, can run into trouble – software that was written for
Windows 98 may not work on Windows XP. Even when running on the
same Windows version, other components of the operating system
may have been upgraded and no longer support the older versions
of your favorite package.

So it may work, but it may not.

If it works you may still have difficulty. In particular,
support may be an issue. While you may be able to get support
from free support forums or other resources it’s unlikely that
you’ll be able to get official support from the software
manufacturer.

Finally, it’s unclear whether it’s ethical to locate and
download software from sites other than the manufacturer’s
approved channels. In many cases, because the manufacturers are
busy on more current versions and won’t support the old ones
they’ll turn a blind eye to old version downloads. In other
cases, because they have a vested interest in making sure people
are up-to-date they may actively discourage the practice.