Rosetta Stone Microphone Problems

We have 20 computers running Rosetta Stone at our ESL computer lab. One computer has stopped recognizing the headset/microphone combo. All computers are running on Windows 7, all software and drivers are up to date. We do not have any USB headsets and are hoping to avoid purchasing new ones due to limited funds. The headset works with Rosetta Stone on other computers. It also works with other speech recognition programs on the original computer. I have reconfigured the speech recoginition settings in the control panel several times.

Error Message:

• When you open a new lesson, the program prompts you to select your device. The window where devices should be is empty.

Solutions we have tried:

1. Renaming the device in the Control Panel
2. Plugging it into other jacks (front and rear panels)
3. Start up and shut down
4. Works on other computers
5. Works with other programs
6. New headset/microphone
7. Adjusting volume/mute
8. Adjusting firewalls to allow Rosetta Stone to access internet
9. Calling Rosetta Stone tech support (they cannot help us unless we purchase USB headsets)
10. Reconfiguring the speech recognition set up in Control Panel
11. Troubleshooting in the Rosetta Stone program

It's frustrating because we have 19 computers with the exact same program, headset and OS working perfectly. Any help would be much appreciated!