Car over heated, now no heat

What is your question?

My 2001 S500 over heated, I replaced with coolant 50/50. Now it makes this sqeeky noise as it runs and loud sqeeky sound as I start it up. There no heat blowing when the engine has reached temp. just cool air. I do not see any leaks anywhere. What seems to be the problem? I am assuming my water pump and thermostat or just the waterpump. Any help would be appreciated.