I am using windows XP 32 bit. I installed Audacity 2.03 version and it was working fine over the last few weeks until one day I tried to record again but this time when I press stop the recoding, the recording cannot be seen, I am using Realtek audio manger.
Here is some pictures to see it more:

While the recording is happening, you should see the red recording meters bounce like this:
http://kozco.com/tech/audacity/Audacity1_record.jpg
and the blue waves should build themselves left to right. If you don’t get those two during the recording, then you’re not getting a show.
You can put Audacity into a test mode. Right click on the red recording meters > Start Monitoring. The meters will wake up and meter your performance without sending Audacity into record. Perform your show and see if the meters bounce.
Koz
Okay I finally fixed it. I uninstalled it, downloaded another 2.0.3 installer and checked “reset preferences” Thank you audacity! Can’t wait for the next Update!
Well done, that was the correct fix. I think Audacity was trying to write to a temporary directory it could not write to. Resetting Preferences resets the temporary directory to a safe default in your user space.
Any time a previous audio waveform becomes silenced (flat-lined) like that you can assume a problem writing to or reading from the drive.
You can always check where your Audacity temporary directory is and how much space it has in the Directories Preferences.
Gale