The upgraded Avast 9 completely wrecked my Win XP system configuration so badly that I had to spend almost 2 days sorting out the problems.
To just mention several:
1, My System restore function was corrupted and I could not restore my system to any earlier points
2. My systray icons and programmes failed to load
3. My repository was corrupted and had to be tested and rebuilt
4. My Microsoft Security Centre is still corrupted and no longer recognises any antivirus programmes
And so on!
I have read other people’s comments on the Avast Community Forum and I can not help but concur that Avast failed to adequately test this upgrade before releasing it and consequently it has caused enormous problems for users.
I have been using Avast since Version 5 and on the whole have had no read problems. However, I am now so suspicious of Avast’s quality control and testing programme that I will never use Avast again.

Hi,
I think you have to wait a little (next 2014 version),avast team says some xp troubles will be fixed in few weeks.

To continue with wittiness to para-noid post here I could say that there are still a lot of people who dive into the water before drowning ;D
one thousand = 500 out of the water + 500 drowned

I agree with Chris05. Not to start any type of verbal shots at each other, but please consider that other brand name Anti-Virus software programs have stopped making their programs to be run on Windows XP computers. I give credit to Avast into having their programs available for Windows XP.

Also, it may NOT be the fault of Avast causing your issues. It could be Windows XP as what I understand Microsoft has stopped Windows Upate on some of the versions of Windows XP.

You mentioned you upgraded to version 9. Did you completely uninstall the other Avast version you had on your computer, please? Did you use the Uninstall Utility that is available for any member to use to remove their Avast from their computers? Did you also use the Add/Remove link in your Control Panel? Did you use CCleaner to remove any old Registry Keys, etc that may have been left from the version you had prior to version 9?

Even if you kept the 9.0.2007 version installed on your computer, there is a Repair option in the Add/Remove programs in your computer.

If you are interested into trying version 9 again, please remove your older versions with the info I had mentioned above. You need to start fresh with nothing left from your older versions of Avast.

I will help you as much as possible if you want to try it again, please.

Thanks for your reply and advice. I did finally completely remove all of Avast from my system, but I am too afraid to reinstall it again. I will be changing my computer to upgrade to Windows 7 or 8 next spring and will soldier on with MSE until then.