Take a read from Razer: http://www.razersupport.com/gaming-audio/razer-megalodon/
Have you updated your firmware (not driver):
Do I have to download any drivers for the the Razer Megalodon?
No, that is part of the beauty of the Razer Megalodon. There is no need to install any drivers on your computer. However, please be sure to update your Razer Megalodon with the latest firmware. Firmware link here: http://drivers.razersupport.com//index.php?_m=downloads&_a=view&parentcategoryid=105&pcid=37&nav=0,78,37
Where can I find instructions on how to install the 2.12 megalodon firmware update?
Here are the instructions to update the Razer Megalodon to the latest firmware:
1. Download the firmware update from www.razersupport.com.
2.Uninstall the current Megalodon driver. ◦Make sure the Megalodon headset is plugged in ◦Right-click on My Computer and choose properties ◦Click the System tab ◦Click the device manager button ◦Click the + beside Sound, Video and Game Controllers ◦Right-click the Razer Megalodon and choose uninstall
3.Unplug the Megalodon headset
4.Double-click the 2.12 firmware update you downloaded in step 1 and follow the instructions.
5.Plug in the Megalodon headset and allow the driver to install.
After following these guidelines from Razor, if you are still having problems post back!