This problem only seems to be affecting Win XP. Others with Win 7 aren't having any problems at all - at least not with any memory leaks. So if you upgrade to new computer with Win 7 or 8 there will be no need to change from Avast. MS SE is not only unreliable and not very good at catching viruses, it also acts as spyware tracking you all over the Internet.
When I get another new computer, if it's got Widows 7 then I'll be reinstalling this version 7.0.1451 of Avast Free. As stated elsewhere I'm currently using AVG 1012 Free until this issue with XP is worked out.
I believe Avast acted irresponsibly and unprofessionally toward Windows XP users with this release. Sad to say, because what happened to the 3-6 months of making sure the update was good before the new version toaster notice came out? That amount of time is what Avast used to have. Customers thought that wasn't enough, so now Avast is pushing out the updates too fast. I don't like having to set the Program Updates to manual, but I had no choice after this release.
I also think that because Windows XP is becoming more and more obsolete, Avast is doing much LESS testing than in the past on Windows XP systems. Millions of people are struggling in harsh economic times, and can't afford to purchase a new computer. Tons of business are moving to "push out and release the new and cool" with lesser regards to quality control in testing than in the past, and that's what's causing problems on legacy systems.
Jack