Nvidia MX440 video Driver "nv"
Unsure if Nvidia have a driver for this video card on their site, but it might be worth checking out.
My Fedora box at home had the same issues with the "nv" driver and I switched to the official "nvidia" driver and haven't had any problems lately.
Originally I noticed the problem surfaced with more regularity when running WoW under Wine, but occassionally it would just freak out randomly. I'm also using Compiz with many effects turned on, so that could have pushed it over the edge sometimes too.. However, I don't play WoW any more, so that may have something to do with the increase in stability too, but Nvidia are releasing updates for it pretty regularly.
The downside is that every time a new kernel is released, you have to re-run the nvidia setup program, so don't delete it.