AshWebsv.exe gives 99% CPU usage.

A couple of times recently my system has slowed down almost to a crawl. I’ve had to shut down all running programs (Thunderbird, Firefox and my Pharmacy program) to even get XP Task Manager to run. Having done so, I find that ashWebSv.exe is using 98/99% of the CPU cycles. Only shutting it down forcibly with Task Manager will stop it - or a reboot. Any ideas where to start looking for the problem? I’ve had to turn it off completely in case it happens when I’m not here, and the locum doesn’t know how to force a shut down.

What version of avast are you using, the latest normal release is 4.6.623