There is no cold air from DAEWOO Air conditioner.

This could be a multitude of things: you said it worked when installed,window unit right anything punture the coil exposed to outside, if so freon leak no freon no cool Secondly is the filter dirty these unit needs to breath to work if its dirty it wont cool. switches in the same position turn them back and forth a few times see if that helps. always look for the obvious first and work your way back from there. If this is the first time you ran it since purchase was anything punctured on install if not maybe it was a lemon take it back if possible if not charging these things are a pain, it will need taps on the high and low side this should only be accomplished by a licensed professional and could be costly. give this a try and goodluck