install avast6 successfully but fail to start it

Avast Free Antivirus / Premium Security
1

I am a new user of avast.Yesterday,I install avast6 free edition in a computer with windows7 ultimate.To my surprise,
after I install it successfully,I can not stat it.An error message tell me "C:\Program Files\AVAST Software\Avast\AvastUI.exe

The application has failed to start because its side-by-side configuration is incorrect.Please see the application event log or use the command-line sxstrace.exe tool for more detail."

I have uninstall the programme for twice ,but the problem still exist. What can I do?

2

Which was your antivirus before avast? Any other security program?
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.
3

Thanks for your suggestions.But,I do not have other security software before I install avast.