Hi, first post in the forum since there were no problems in the last 5 years using Avast.
After upgrading successfully to 5.1.864 and restarting, there was a BSOD stating "aswsp.sys attempted to access a non paged area".
Rebooted and same message again. Uninstalled Avast in safe mode, downloaded the full 5.1.864 installer, reinstalled (all went smooth), performed a quick scan with no problem and after rebooting again the same BSOD.
I had to revert back to 5.0.677 were there is no problem.
System XP SP3