Windows 7 Home Premium x64 SP1
avast! Free Antivirus 7.0.1426
Online Armor Free 5.5.0.1616
Mozilla Firefox 13.0.1
Shockwave Flash Plugin 11.3.300.265
Build .1451 was a complete disaster, both IE and Fx freezed, so I was glad that .1456 came out so soon... but that turned out to be a disaster as well and avast! staff seems to choose to ignore this problem. When I first installed .1456 surfing appeared to be ok, but Fx freezed when trying to open websites with Flash content. I uninstalled avast! using aswclear.exe and reinstalled (about 20 times or so), but it didn't work.
A poster suggested to me to uninstall and reinstall OA Free as well. Uninstalling avast! and OA and then reinstalling avast! (not OA) seemed to solve the problem. Fx functioned ok. But then problems started again when I installed OA (I set up exclusions rules in both avast! and OA to ignore each other).
Shutting down avast!'s Behavior Shield also solves the problem. Of course, uninstalling avast! completely solves the problem too.
I've been using avast! for many years, I've installed it elsewhere and advised users to install it. I never had any problems (except for that one time when there was a case of false positives). I've downgraded to .1426 which is working fine, but if this problem isn't solved, then I'll probably have to dump avast! and switch to Avira. And one other thing, users on this forum (and avast! staff as well) seem to ignore that people are having problems. I too have encountered systems that are working fine with the latest avast!, but it's also clear that several people are having problems.