I am not able to view the Wave form while recording


All I have been using Audacity for quite some time now however from last four to five days I am not able to see any wave form on the track while recording and only if I apply compressor I am able to see the waveform, I have adjusted the gain on my interface, changed the mic but all in vain. Can someone please help me how to resolve this issue.

What sort of mic are you using?
How is it attached to the computer?
Which version of Audacity (look in: “Help menu > About Audacity”)
What are you trying to record?