What is crawler .com @ why if i deleted it from my computer is it still on it?

i don't remember downloading crawler .com it kept poppin up so i went into my computer and thought i deleted the program... its not listed on my computer anymore but everytime i loggon its my new home page... please help im still peckin my nway thru technology only been tex messegin 3 mons since this crawler stuff got on my pc its running slower i even let the computer gods know that was why i was deletin the program