some of you reported an instant blue screen (or sudden reboots) after applying the latest avast program update. It turns out that this results from the program not being correctly updated (for whatever reason). To make long story short, the problem is caused by the fact that one component of avast is updated properly and second is not - and while these two components try to talk to each other, bad things start happening.
The solution is to boot into Windows Safe Mode and invoke avast program repair
(or, alternatively (if this doesn't work), boot into Safe Mode, uninstall avast and then install it again).How to boot into Safe Mode
To get into the Windows 2000/XP Safe mode as the computer is booting press and hold your "F8 Key" which should bring up the "Windows Advanced Options Menu". Use your arrow keys to move to "Safe Mode" or "Safe Mode with Networking" and press your Enter key.
Note: With some computers if you press and hold a key as the computer is booting you will get a stuck key message as the computer is booting. If this occurs instead of pressing and holding the "F8 key" tap the "F8 key" continuously until you get the startup menu.After you successfully boot into Windows Safe Mode,
go to Control Panel -> Add/Remove Programs -> avast Antivirus -> Change/Remove.
A dialog box appears, with choices on the left. The last choice is "Repair" (you usually need to scroll down the list to see it). Select it and click Next.
If the Repair procedure succeeds, you should be all set. Otherwise, use the uninstall option to remove avast. After the computer restarts (no need for Safe Mode anymore), you can reinstall avast by downloading the latest version from our web servers.