Problem with Avast 5.1.864

Hi, I have been using Avast Free from very long period but have never encountered this problem. Previously Avast Free 5.0.667 version was working fine and no problems were noticed with OS and Avast Program,but after updating it to 5.1.864 version my system has stopped working(After Restarting). At my system startup no other programs are starting(avast too),but if i install Avast and install old version(5.0.667)my system works fine. Even i have scanned my PC for errors and virus,but every thing was fine.Even some of my friends encountering same problem.Please help me with this. Thank You.

PC Configuration:
Windows XP Pro SP3
1GB RAM
160GB HDD

I suggest an installation from scratch:

  1. Download the latest version of avast! Uninstall Utility and save it.
  2. Download the latest avast! version and save it.
  3. Uninstall avast from Control Panel (if possible). If, for any reason, you can’t run it, try booting in Safe Mode and doing it from there. Anyway, boot after that.
  4. Run the avast! Uninstall Utility saved on 1. If, for any reason, you can’t run it, try booting in Safe Mode and doing it from there. Anyway, boot after you’ve run it.
  5. Install avast! using the setup saved on 2. Boot.
  6. Register your free copy or add the license key for Pro.
  7. Check and post the results. If, for any reason, you did not solve, try doing the step 3 in Safe Mode anyway.

Hi Tech,I have followed all the steps you’ve said but the problem still remains.Even i have downloaded and installed fresh package which was newly released.But problem still remains. Even my friends followed your steps but even their problem still remains.I have also installed trail version of Avast!Pro Antivirus and same problem occurs.I think so a new patch should be released. Thank You.

http://forum.avast.com/index.php?topic=68927.0
asyn