my start menu is gone

how can i get my start menu back? i am running windows xp home, my husband says he did nothing but double click it and now its gone. i looked in the trash as well as all the corners of my desktop but it is not there. i thought if i went to the event log i would be able to see what happened, but i could not. when to control pannel, start menu or task bar can’t remember, it said it was all right but i still have no start menu or task bar. to shut down i have to cntrl alt del, which by the way does not show exsplorer is even running, and choise to shut down from there.
help!