Central Air Unit Not Cooling House

[BrendanMowgli]

I have 2 units- one upstairs and one downstairs-

The upstairs is blowing- I feel the air blowing- the thingamabob outside (can't think of the name) is operating, but no cold air. I did notice that there's no water being pumped out.

I hear its the compressor, but hopefully it's something else. Is there a few other checks I can do before I call the rapis- I mean the HVAC guy?

Thanks!