i have music creator le5, worked great for awhile, then after i upgraded to get the mp3 conversion file my headphones  stopped working with the usb mic. i can record but not listen with headphones simultaniously, when i play back i have to remove the usb mic and disconect the headphones from mic and plug into my computer directly through the headphones jack. as you can see this makes recording multiple tracks impossible. ran sound card checks all says ok.

There's a sticky in the LE forum about using USB mics. Maybe you find useful info there. USB-mics can be a real PITA because they are actually soundcards, and because many of them don't offer all necessary functions and/or don't have good drivers, you need to use your mobo soundchip as well. Then, using two soundcards leads to many kinds of problems regarding clock sync etc.
 
Make sure your USB-mic is selected as both record and playback timing master.

Kalle kinda said it all. We don't recommend using or trying to use a USB mic with MC or any Cakewalk product. They just don't cut it.

Welcome to the forum.
From what you wrote, it looks like the USB mic is one of those that is also an audio interface. What model is it?
Did you go to their web site and download/install the latest drivers for the device and your operating system?
What Driver Mode are you using? If the ASIO driver is available, use that.