klh1984, you could copy “400.vps” (C:\Program Files\Alwil Software\Avast4\DATA) from old installation of avast!, then install avast! again at the same directory, then puste “400.vps” in the C:\Program Files\Alwil Software\Avast4\DATA, reboot. In thise case avast! would work with old key and new virusbase.
P.S.: Vlk, I’m sorry. May be it’s not good\legal advise - don’t bun me 