Replying to Ppl who no comps

i realy need your help
my comp is like totaly messed up
well this is what happend i was just using my comp and it kinda started to mell like urnig plastic and it shut off so i was like o it prolly just overheated or sum shit so i wait 10 min and turn it back on it works fine for anouther 3min and then the sae thing happens be this tim wen i try turn it on it says like harddrive error or something then restarts now wenever i try turn on my comp it says like error booting plese boot or select boot and reboot or somthing i have no idea what to do i have 60gigs worth of moves and programs and stuff on my comp which i cant afford to lose can some oneplease tell me what to do ill make sure you get somthing out of it
ill try get pics of what it says by tommorow thanx