Log on as Administrator

Recently we suffered a power lost and my system went down. Upon restoration of power system restarted and the dreaded blue screen came up, system was switched off and restarted about twenty minutes later, it started up normally, when completed half my desktop icons had gone, all by email addresses were gone, when I tried to restore the system it said I do not have administrator rights. I checked the help files and the runas cmd & it kept asking for password which I have not got a clue of as I did not give password when I setup XP pro, any advice would be helpful so I can get my administrator rights back, being in Germany there is no one in my immediate area I can ask for help. Regards