I have a 7-year-old Carrier window air conditioner (6000 BTU) that seems to work okay, yet it doesn't cool my 1,400 cu. ft. room. It produces cold air (though my wife thinks it's not as cold as before), and the last time I used it--about 2 years ago--it could freeze a room. Now it can only slightly cool a room after running for a long time.

To prevent warm air from entering the room, I put towels at the bottoms of doors, and made sure windows are shut tight. No help.

If the problem is the air conditioner itself, and not the room, is the solution to toss it and buy another? Does anyone service these things and would it be worth the cost?

Probably cheaper to buy new one than to pay a tech to service a 7 yr old unit. However, it is probably dirty and cleaning on the coils (condensing and evaporator) thoroughly could help it to cool well again. Dirty coils will cause unit not to cool properly