You have probably done all the stuff below but i thought i would include it in case you had missed something and others may find it useful.
I had a problem on my laptop (windows 10) because HS didn't want to work with my headset which was one of those with two jacks, i gave up in the end and got a USB headset having read about others having the same problem in the forums its been fine ever since.
Headphone set up is one of the main things that causes problems with HS 3 & 4.
I hope this is of some help.
Installing instructions HamSphere 3.0
1. Java: Make sure your PC has the latest Java from www.java.com
2. Microphone: HamSphere needs an active microphone connected to your computer. Headsets are preferred.
3. Windows: Download the EXE installer and run it. Follow the instructions.
4. Windows 8, 64-bit:You must install Java version 7, release 10 and above. Also you need to run HamSphere as Administrator. Download the JAR file, save it on your desktop, right click and Open As "Open with Java (TM) Platform SE Binary".
5. Linux or Mac: JAR files are Java runtime executable files. Never unzip the jar-file even if suggested. Save the jar file intact somewhere on your computer, like the desktop and right click "open with" Java (TM) platform binary.
6. Linux: Save the jar file as hamsphere.jar in your home directory. Open a root terminal window and execute java -jar hamsphere.jar
A word about firewalls: If you get white screens when you launch the HamSphere transceiver, the firewall is blocking it. HamSphere uses TCP port 80 and 8010 and it is important that the HamSphere application is allowed access to web pages via port TCP 80 and communication via TCP port 8010. In some Windows 7 and 8 installations, JAVA applications are automatically blocked in the Windows firewall and you must open the ports manually.