System preferences is missing and how to get it back.
hi. i am using the old version of mac os v 10.5.8 and recently my system preferences had already missing. how can i get back the system preferences since i can't change my desktop background. then, how to change the v 10.5.8 to the latest one? do i need to pay or just downloaded it? how much it costs? and i would like to upgrade my microsoft office to the latest one as i can't do my work well with the old version of 2004 microsoft office. i hope there is some response and solution from u. thank you.
MacBook, Mac OS X (10.5.8)