AC Compressor locked up?

Hello, needing feedback on my SUV. She has been running alright since I bought her a few weeks ago. The A/C has blown icy cold and today on our way to town noticed it stopped blowing cold air when idling. On the way home we cranked the A/C to high and added some speed (from 55 mph to 65 mph) and in doing so there was a loud screeching sound and smoke coming through A/C vents (just briefly though) and a slight melting plastic/rubber smell, then abruptly the engine shut off. We coasted to the side of the road and popped the hood. The smoke and smell were very quick then gone. The serpentine belt looked a little frayed and worn. When attempting to start engine it will only slightly "clunk" over but wont turn over or click over. Please help. Any information will help.