Avast 4.8 Paralyzed Computer

Avast updated itself last night on my computer. Immediately after restarting my computer, an error message popped up that said: “INI file Modification error. A program is attempting to modify an avast INI file, possibly changing some of its system-wide settings. Some of the settings can even disable avast realtime protection. Do you want to continue?”

If I click on “No,” it causes my computer to stop functioning to the extent that I cannot open any programs. If I click “yes”, the same thing happens. I cannot open any program. This includes not being able to open the program to turn off my computer, not being able to utilize the control-alt-delete function, not being able to do anything.

This has basically rendered my computer useless.
My relevant information is:

I am using Windows XP.
I am using the 4.8 Home Edition of Avast.
I amusing the VPS file version 080409-1, compilation date 4/9/08
I connect to the internet via wireless.
I cannot access the basic configurations of my computer because, as previously stated, I cannot open programs on my computer.

My obvious question is, what should I do?

Please, do not duplicate posts and the effort of help.
Follow http://forum.avast.com/index.php?topic=34602.msg290168#msg290168

I wanted to respond on this topic since I have a similar although not as dibikitating problem:

AVAST updated last night to 4.8
I started getting the Avast ini modification message as indicated in Platatoos first post; the offending program is a sidebar installation of Google Desktop Search.

Vista 64bit
Avats 4.8
latest virus definitions

However, I can say yes or no and continue to use my computer. The dialog message reappears at regular intervals and I have to dispatch it.
Google’s sidebar appears to function whether I answer yes or no. I have RSS feeds and Google calendar loaded (plus a clock).
I have changed the sidebar to just the floating desktop search and the dialog message about changing the Avast ini appears to have stopped.

This problem should be corrected… why is it reappearing?
http://forum.avast.com/index.php?topic=33634.0