Computer helpp

hi guys well i went to work today and got back home tonite and i logged in my computer and all my bookmarks were gone from firefox… HELPPP and also the theme was defaulted. also when i start up the browser and try to add custom stuff to the toolbar when i reboot firefox it is not there every time :frowning: please help what the heck am i getting hacked ? first windows password wouldnt work now firefox is messed up