After updating to Ubuntu 11.04 my computer started to turn off and reboot. This happens about every half hour, I think there is a tendency for it to happen when I work with multiple applications at once.
It is both my Desktop and Laptop.
I have installed BOINE Manager, PlayOnLinux, Gimp, Qt, Wine, VLC-player and Blender. Otherwise is all as default.
See my /var/log/kern.log.1 here: http://paste.ubuntu.com/608690
When I run Memtest 86+ I get this error: