Odd that your installed kernels are all for 10.10, but the release is
said to be 11.04 - possibly an aborted upgrade?

One thing is for sure: the system won't upgrade to a new version unless
directed to, so either you inadvertently started an upgrade, or someone
with access to your system is playing tricks on you.

There is a checkbox in the system update GUI that, if checked, will
upgrade the OS to the next version, but it's disabled by default.