Problem with avast! 7 free and Private Firewall (and not only)

avast! 6 free and Private Firewall 7.0.26.4 was working together flawlessy on Win XP Pro SP3
Instalation of avast! 7 free via built-in updater cause continuous problems with window pressing
to participate in Community.
Unchecking on this window (and/or via Settings window) was not succesfull i.e. after each reboot
mentioned window appears on the screen.
Uninstallation of avast! 7 and next regular installation resolved problem with window.

But, in each case, avast!7 and Private Firewall 7.0.26.4 causing computer working slow, heave and
rather not responsive well.
Private Firewall folder is declared as extension to shields and also to scanner - without result.

Just for checking after removing avast! 7, Avira Free 12 was installed.
Avira and Private Firewall working very well.

I think, something is wrong with actual version of avast! 7 free, because PF with other
AV working OK. (I also made a test with Vipre - also without problems).

Best regards
William