cracker in my computer

[fifa]

I've just got started with linux (just 2 weeks) and a guy of the same Linux course of mine deleted all tha man pages and half of files. :'(
I am quite sure he didn't know my root password, but my ssh door was open... ::)
Then he deleted also the log's files, so I don't have any clue of what happened in my pc.

How can I know who entered my pc? :'(

Please help me.

[whoiam55]

It's kinda hard to know in current situtation as you already stated "He deleted all log files". can you post your question here http://neworder.box.sk ? I'm sure you will get much more help than here, As kubuntuforums.net is basically a linux related site (not a security related). Follow this link to prevent this in future http://kubuntuforums.net/index.php?topic=775.new#new