The window unit that is freezing up might have a bad cold control. Dip the thermostat probe in some ice water and see if the compressor will shut down. if it continues to run replace the thermostat. If it shuts down then get some foaming cooling coil cleaner (non-rinse) and apply that to the inside coils. The second unit either has a bad overload (mounted atop the compressor or a bad/weak capacitor. Get a HARD START device from the appliance parts store and go by the directions. Part number HS650. TIP: if you do not have room to mount the hard start mount it outside,run the wires through the wall(keep the hardstart out the water/off the floor.