I don’t know where to post this, but I will post it somehow. I’ve had many problems with Audacity. but I was able to fix it. This problem has made me stop recording. At first my microphone started fading out and not make any sound at all. Then, after a while, this happened:
I don’t know what to do now. 
Are you on WinVista, Win7 or Win8?
You posted two very different problems and linked them. We reeeeely doubt they have anything to do with each other.
What kind of microphone do you have – model numbers – and which Windows?
What’s the show? Are you recording your trombone solo?
Different answers to these questions point us to different solutions.
Koz
I’m using a Rockband microphone. I’m recording myself singing. I’m using Win8.
Guitar-Hero Rock Band USB microphone?
Cool.
Plug the microphone in, wait a handful of seconds and restart Audacity.
Audacity > Edit > Preferences > Devices > Recording: Pick the microphone, mono. [OK]
Audacity > Edit > Preferences > Quality > 44100, 16-bit. [OK]
Press record and you should be able to make sounds into the microphone and the red recording meters should bounce and there should be blue waves on the timeline – although you might not be able to hear it yet.
Something like this:
http://kozco.com/tech/audacity/Audacity1_record.jpg
Now go into Windows control panels and turn off Windows Enhanced services according to these instructions.
http://manual.audacityteam.org/o/man/faq_recording_troubleshooting.html#enhancements
And then finally, use the Audacity output device drop-down (speaker symbol) to select your regular speaker system or headphones to hear what you’re doing.
If you have a live microphone, you should have headphones. Microphones and speakers don’t get along well in the same room.
Did I lose you and where?
Koz
By the way, voice echo or delay in your headphones is normal. You can’t quite do real time sound-on-sound overdubbing with a straight computer soundcard.
Koz
Bump. I wasn’t clear when I posted this.
I can’t record anything, the Mic has nothing to do with the problem. Every time I hit record, I get this error:
I can’t record anything, the Mic has nothing to do with the problem. Every time I hit record, I get this error:
If you get that error when you’re trying to sing into the microphone, then the Audacity sound settings and the microphone sound settings are different.
That was this part of my reply.
Audacity > Edit > Preferences > Devices > Recording: Pick the microphone, mono. [OK]
Audacity > Edit > Preferences > Quality > 44100, 16-bit. [OK]
See if that doesn’t make the error go away.
Those are normal settings for a lot of microphones. If it still doesn’t work, try setting stereo instead of mono.
Koz
The fading out thing is probably a Windows problem. Turn off Windows Enhanced Services. That service is intended to help with your voice when you conference or Skype. It kills singing.
http://manual.audacityteam.org/o/man/faq_recording_troubleshooting.html#enhancements
Koz
One other note. Audacity looks for new microphones when it starts. If you start Audacity first and then plug in the microphone Audacity won’t see it. Plug in the microphone, wait a couple of seconds and then restart (or restart) Audacity.
Koz
This doesn’t help at all. I can’t find “Pick the microphone, mono.” Audacity can’t find my mic.
Topic moved to the Windows forum.
Is that a USB microphone?
Look in the Windows Sound Control Panel. Is the microphone listed as a recording device and enabled?
Note that the microphone must be recognised by Windows, enabled and working, otherwise Audacity will not be able to use it.
Open Audacity after ensuring that the microphone is recognised by Windows and is enabled and is working (green meters in the Windows Sound Control Panel respond to sounds into the microphone). Then select the microphone (which will be listed as a USB device, if it is a USB device) in the recording device settings of the device toolbar.
It is saying that no devices are installed. Audacity says the same thing.
It would help us to help you if you gave more than one line answers. We cannot see your computer.
You get “error opening” because you have no input devices in Device Toolbar .
You cannot record with your mic if Windows does not see it.
If it is a USB mic, try following “Detecting USB and Firewire devices” here: Audacity Manual . Be sure to try another USB cable.
If you want to record from other inputs such as the pink mic input that belongs to the Realtek computer sound card, you will have to enable those inputs in Windows “Sound”. I suggest you go through everything here step by step: Missing features - Audacity Support .
If you cannot enable any inputs in Windows Sound then what is the make and model number of the computer? If it is a branded computer like Dell or Lenovo, you should go to their web site, search for your computer model then make sure you obtain the latest audio drivers for that model and for your version of Windows. I assume from the design of the dialogues that you are on Windows 8. Please confirm that.
If your computer is 64-bit then you must get the 64-bit audio drivers for your computer. Right-click over Computer and choose Properties to check if you have a 64-bit computer. If it does not say 64-bit then it is a 32-bit computer.
Gale