HP Pavillion zt1231s computer

Question

My computer life lasts half hr tops and wont become portable, and wont last on battery which, it used to be able to d0. before it goes off the fan makes loud buzzing sounds and the light flashes red;; i even have to type this up quickly. Then, i switch it back on and the power pack gets real hot. also i quickly run out of disc space--HELP!!!