I am already aware that there is a conflict with ISBoxer which wont allow me to press my "PTT" button
Run Ventrilo as Administrator and you can use your PTT button (google for ventrilo isboxer and one of the top results is an isboxer.com article titled "How to fix the Ventrilo push to talk hotkey"... with this info )

I can't tell you anything about the voice software though.