Further to my previous post, I thought I’d try Avast again (in view of the updated program) on one of my XP machines that went into a re-boot/shutdown cycle after updating previously. I completely uninstalled when that happened in safe mode and have been running with no AV program at all for a while since then. Installed the 2014 version but still no luck at all. Didn’t even get as far as the desktop before it went into a BSOD with a paging error, so that just about finishes me with Avast, I’m afraid. I’ll keep it running on my Win 7 machine, as that seems to be the only one that it runs on successfully but it looks like the XP machines are going to have something else installed, AV-wise, but I’m not quite certain what at the moment.