[TriLUG] silly kill question

[linux r]

[linuxr at 150 home]# yum install opera
Existing lock /var/run/yum.pid: another copy is running. Aborting.
[linuxr at 150 home]# ps
  PID TTY          TIME CMD
13655 pts/1    00:00:00 bash
13700 pts/1    00:00:00 ps
[linuxr at 150 home]# killall yum
[linuxr at 150 home]# yum install opera
Existing lock /var/run/yum.pid: another copy is running. Aborting.
[linuxr at 150 home]#

1.  What am I doing wrong here and how do I get rid of whatever is running?

2.  How do I tell when I have a 'lock' running, if it doesn't show up
with ps?  Isn't ps the list of ALL processes that are running?  Is
there something better than ps to use?

3.  How do I 'kill' ?  I can't see the process.  Also in the past when
I have tried 'kill 8232' or whatever PID it was, it didn't work.  That
used to work for me in a unix distro.  Not sure what has changed but
the man pages haven't clarified it either.  So how do I kill a running
process correctly in FC

Thanks in advance
Marc