My Audacity's Play bard does not move when I press 'Play'

Using Audacity 2.0.2 (however the problem persists even after upgrading to 2.0.4) on a Windows 7 64-bit Desktop.

I was attempting to mix two songs together and was doing fairly well until I wanted to add an Echo to a certain section. After hitting preview for the Echo effect the ‘Remaining Time’ begins to rise exponentially to no end (this persists with any effect’s ‘Preview’ button).

After this event whenever I pressed Play/Space Bar, the green Playback arrow would show up where I set it however it would flicker and not move. I can still edit and move around the audio clips but without being able to hear it back hinders my ability to know if it sounds right. Restarting, Updating, and trying a new Project does not do anything to change this problem.

Here is an image of the Preview Problem. As you can see, it is predicting hours of time needed to add echo to a clip less than a second long:

Any help would be appreciated, as i was close to finishing and had my hopes up.

Thank You.

How much free hard drive space do you have? Audio (and video) production sucks up drive space at a good clip. Every time you do an effect, Audacity has to save an UNDO version of the song. It can run into a lot of data in a hurry.

How do you get out of that? Are you pressing the Stop button to close the preview dialogue screen?
What sort of sound card / audio device are you using?
What settings do you have in the device toolbar?