I cannot hear playback through my speakers. I am able to record. The blue waves are
going across & the green bars are moving, but I cannot hear playback.
I am using a Rode NT1-A mic, a MicPort Pro preamp. The phantom power is on. I am running
Windows Vista & I installed Audacity from the .exe installer.
I use Audacity for Voice Over work. I previously used a Snowball USB mic & could hear playback
with no issues. I am running the latest version of Audacity. 
Please help.
Monitoring through speakers while recording with a microphone is a bad approach because the microphone will tend to pick up the sound coming out through the speakers as well as the sound that you are trying to record. At best it will tend to make the recording sound echoey, and at worst the speakers will start screaming with feedback. Much better is to plug headphones into the headphone socket of the MicPort.
Did you try listening to the headphone connection on the MicPort? I bet that’s where the sound went. It’s not unusual for Windows to see a bidirectional driver and assign sound to both directions.
You can try adjusting the Audacity Device Toolbar.
http://manual.audacityteam.org/help/manual/man/device_toolbar.html
Or you can go into Windows and assign your speakers in the Control Panels.
Koz
Koz, Thank you. And maybe I did not explain my problem fully enough. I
am not trying to monitor through the speakers. I want to listen via the speakers
after I record.
Set the Output (Playback) device in the Device Toolbar to the output that is appropriate for your speakers.