What could be wrond with my air conditioner?

I live in an apartment complex, and recently, i have had problems with my air conditioner. I dont get any air through my vents at all. its an outside unit, and upon inspection, i found that copper pipes coming from the condenser and becoming exposed and starting to freeze up. the motor and fan are both running, and i have let it thaw several times, but it always end up freezing. i also cant get it to run in "fan" mode. (no heat or cooling, just pumps air.) but that wont give me any air either. i fear it may be an issue with the charge or the coil, but then i would even be able to get heat. my intake vents are clean, and open, but still no resolution. im going to speak to my landlord this week, but i wanted to get a little more insight. please help!!