Using XP pro, service pack 3. Zone alarm firewall free without anti virus. Free version avast! After installing latest update, computer would get to start up, I signed in then nothing happened for 4hrs. I restarted, then I got the blue screen! Thought I got a nasty virus. Scanned with malwarebytes, found some adware, nothing major. Tried to restart, still the same problem. I reinstalled a back up of my computer, then everything was fine. Updated avast then tried to restart. I repeated the whole previous process because I didn't think avast! was the problem. 3rd time now, suspecting it may have been avast! update, I ran my restored computer through a few processes. Went on the internet etc. I updated avast! again (banging head on a wall) and yep, you guessed it. Computer crashes again. Now, however, I know it's the avastt! update. 3 days wasted and right in the middle of a photo project. Way to go avast! Didn't these years of the same complaints make a difference? I'm taking avast! Off my computer and never going to try this again.