Do you have sound problem when using VoIP softphone or dialer with Microsoft windows vista and windows7? Are you facing this issue when you are using Betamax /dellmont VoIP software?
I can list out some common issue regarding sound when you install voip software and try to call using the softphone below;
1. You are incapable to hear sound from softphone.
2. Lot of interruption in sound when you speak.
3. Your friend is unable to hear voice.
4. You get error: the call failed due to sound device problems in this computer.
5. Even changing the sound device or running sound audio wizard does not solve the issue.
6. And you can see all your other application like media player and all are working with fine sound.

As far as I seen the issue the sound issue is related betamax product such asVoipBuster, VoipStunt, InternetCalls, VoipDiscount, FreeCall, VoipCheap, PoivY, SparVoip, NetAppel, SipDiscount, WebCallDirect, LowRateVoip, JustVoip, 12Voip, Nonoh, SmsDiscount, VoipWise, VoipRaider, SmsListo, BudgetSip, VoipHit, DialNow, CallEasy, InterVoip, VoipZoom, SmartVoip, ActionVoip, Telbo, Jumblo, VoipBlast etcwho are the provider of cheap rates phone calls to India, Pakistan , Bangladesh etc.There are lots of freecall users especially in UAE who already having some other issue like voip ban by Etisalat so Etislat Blocked Freecall ,action voip etc.
Issue:
If you are using Microsoft windows vista or windows7 and having compatibility issue of the software with this version. In this case the sound card gives error and both parties cannot hear anything.

Solution:
Follow the below steps to solve the above issue
1. Go to program files in the computer and locate your voip application folder.( It will be in C:/ Program files)
2. Find the voip executable files in that folder.Most probable it ill be the provider name with exe extension ( eg: Actionvoip.exe,smartvoip.exe,freecall.exe)
3. Right click on it ,go Properties and select Compatibility
4. Put a Check mark on (Select) compatibility mode with windows xp (Service pack2)
5. Press ok and restart the application.
Now I think your voip softphone sound problem get soved.
I am expecting your valuable comments by using this solution