2010 Mitsubishi sent up with the car just idling. The compressor isn't working because belt isn't turning & sparks & smokes a little when cranked

The compressor isn’t working because the belt isn’t turning causing it to spark and smoke a little bit when I crank it. That’s without the AC or heat being on. Also, when I drive it it makes the loud squealing noise until I accelerate up to a good little steady speed then it quiets down to light squeak until I slow down again. When I get ready to stop sometimes it just does on it own. So what could be the problem?

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Update from OP:

2010 Mitsubishi Galant SE making horrible squealing noise and the RPM’s go up while just idling is what I meant!!!