I am part of the IMVU chat portal and their new client is shutting my computer off?

IMVU is a virtual chat portal and has a lot of graphics. I do design and 3D developing there. It’s really nice, if none of you have seen it. They do update their client regularly, this time, as sometimes before, it simply turns my computer off. So then it powers off and restarts. In the past I have asked for older client versions to use, this helped but cant find one currently. Is there anyway I can stop it powering down? Everything else is running OK on my system. I am on XP Prof.