It's driving me nuts I have this process running called "operamotifwrapper", it has been on since I started browsing this morning, and it can't be killed. After I shutdown opera, it is still using about 50% of my cpu, and it has something to do with loading the flash plugin. I already tried killing it using 'kill -5' and 'kill -9', but it didn't work. Can anybody help me on killing it?

Try

killall -SIGKILL [proc NAME]

^not at a linux machine so i'm not sure if that will work^

It didn't help
I guess I just have to reboot (oh no, windows logic :P).

It might not be killable if it is busy or waiting for something at a lower system level. (did that make sense???)

I found a thread concerning troubleshooting operamotifwrapper HERE .

Might not be an answer, but might get you pointed closer to the right direction.

BTW, I prefer Mozilla and Firefox.

usually, only process that can't be killed are process marked "D" (dead I guess?) on a ps -xa command. This state mean an Input/output failure most of time (dead hard drive, broken network connection, very bad bug, ...). For others process, you should be able to kill them with the "KILL -9 process_number_here" command. -9 mean KILL (you can write KILL -KILL of most recent system), it is the (I think?) highest level of kill. Very fews apps will block this kill signal.
The only case (that is probably your case) is when the process is child to another process. I think operamotifwrapper (damn crap according to me, you can prevent this to run typing "chmod -x operamotifwrapper" in the opera plugins directory (/usr/opera/plugins ?) ) is a child of opera or mozilla. You should kill the mother process first, then the child should die then.

Oh and... if you got a "Z" state (Zombie), this usually mean the process crashed and died but is stalled in memory. This doesn't happen often our days, but if you see one, you might have trouble to kill it.

Zombie processes can't be killed. They are already dead.
Zombie processes happen when a process doesn't return from execution as it should.
The only way to get rid of zombie processes is a reboot.

Zombie processes should as far as I heard not take up any memory and no processor time. The only issue is the annoyance factor

Thanks for the replies, I think it was in state "D". I couldn't kill it, but when I went out for dinner and got back, it wasn't listed at 'ps aux' anymore, so I'm happy. And btw rip, I have firebird installed on my system, but I don't like it that much, so I can't be bothered to update it to firefox

next time, I would advise a shotgun and a machete...

but that's just one man's opinion...