can't get rid of user called nobody
 

I have this login user named "nobody" that sometimes
appears when I'm running top. nobody often runs find,
but also other programs, but he appears and disappears
so fast I sometimes can't see the PID and I'm too slow
on the kill command.
I have looked into the system and there is no user, or
group, named "nobody". I don't like this. Something is
wrong. Does anyone have any ideas what might be going
on here ? Who is this "nobody" and what does he want
from a simple home computer user who never banks or
even purchases anything online ?
Any ideas would be welcome.
Oh, I'm running an obsolete computer with obsolete software,
( Ubuntu 8.1, Gnome 2.24.1 ) because I'm tired of buying
the newest this and that just to be "obsolete" within a week.
I'm not made of money.

:-), "nobody wants nothing from you".. It's a simple user that comes by default in ubuntu..
Check for /etc/passwd file and you will find an entry related to it. If you are so annoyed, you can delete it by "userdel nobody".. but i will suggest not to.

The "nobody" user is a pretty standard *nix user, that a lot of system services run under. It's totally normal.
You can download and install a new version of Linux anytime, for free. Unless you've got a very, VERY old computer, you can use a new distro anytime you want.

Unless you are using a LTS, Long Term Support, version of Ubuntu, you would have stopped receiving updates for this a long time ago, which will leave you vulnerable to all sorts of nasty treats. You are also not getting the benefit of improvements and new features that have occurred over the last couple of years.

AIUI, it's a simple security device. Many services are set up to run under the limited "nobody" user if they don't need any higher level permissions to operate. If someone manages to compromise that service, they are still restricted to only what "nobody" has access to, which isn't much.

I recommend just leaving it alone.