Posted on 18th Jan 2010 @ 4:35 AM

Download and Install  Avast 5.0 Free AV  First Beta [version 5.0.70]

Download here:http://files.avast.com/files/beta/5.0/setup_av_free.exe

It should be possible to do the installation over existing v4.8, but this feature is still somewhat experimental so my suggestion would be to do a clean install (i.e. remove the current version of avast, reboot, and then do the install of v5 beta).