Vista - msn conversations

Hi. My problem is that my laptop was taken by a dear family member and he
sais he found some valuable info from the hard drive or somewere else there
about what I had been chatting in msn but I just dont know how because I
didnt click the "save conversations" button so they arent supossed to be
there. I just want to desperately know where is the taking that info, are all
conversations storered? as well as sent emails in hotmail and msn adresses
Ive been talkin to? This is really urgent, Im in jeopardy and I just want to
make sure he isnt blackmailing me with this.

Best regards