Can't kill process and uninstall package

I had some problems: couldn't remove packages properly and eventually I did rm -rf to directories of Virtualbox. Now I want to install Vitualbox again, but can't because system tells that virtualbox already running. I tried kill -9 <PID>- doesn't help. Every time I try ps -aux | grep virtualbox the process appears with new PID. `

30507 0.0 0.0 15444 944 pts/0 S+ 15:00 0:00 grep --color=auto virtualbox

I can't remove, purge virtualbox. And it seems I don't have inittab.

Update: I'm not using those broken system already, but still would be nice to know how to deal with such kind of problem.

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