Unfortunately, ddalbiez suggestion does not work for me.
Uninstall using aswclear.exe in safe mode appears to remove avast.
Re-install version 7, all appears to work, free licence is back in place (with auto-updates).
Runs fine.
Switch off. Re-boot, still fine.
Re-boot next day and get BSOD again.
Can Avast somehow be affecting windows boot? Very strange.
Next step is ditch avast completely, use AVG, see what happens.
Similar story here. Avast 8 prevents boot in XP SP3.
No Zone Alarm, never used it.
Do have AMD chipset.
Can get back to 7.0.1474 from system restore.
All works fine until switch off.
Then the next boot fails again - very strange. Is Avast "corrupting" something in the windows boot files?
Trust we will not get "XP is too old to support" from Avast. Can accept a bug on a on operating system, but so many still using, we do expect a fix.
I suggest you do a clean install of Avast 7:
-download the avast cleaning tool
-download Avast 7, e.g. from oldapps.com
-boot in safe mode, uninstall Avast using their cleaning tool
-reboot in normal mode
-install Avast 7
Did this solve your problem?