Not sure what you have tried already to get Vent to work, but since I am good at breaking software I have learned a little about how to fix it, too
. Here is a rundown of the things I do when my Vent stops working (like daily, LOL):
1) In lower right corner of Windows desktop is the speaker icon. Left click, then click playback devices. This brings up window. Make sure the device you prefer for Vent (headset?) is set to default. Then, on the same window, at the top check the recording devices default setting and correct if needed.
2) Same speakers button, left click, make sure volume is not turned down. Mine turns itself to zero somehow :/ on occasion.
3) Make sure your headset volume is turned up and on - do you have a volume wheel on the headset? (maybe this should be #1)
4) In Vent, go to setup and make sure that your headset is the default device for both input and output. Then hit OK. Until you hit OK your changes don't take.
This usually fixes things for me. Whenever my headset gets unplugged I have to check ALL of these things every time. There are a few more settings in Vent that can get messed up, too. Just read the Setup page with Vent running, you will be well versed in Vent in like 10 minutes.
Hope this helps!