Custom sounds? Using Onboard sound by any chance? Do you use a transmit key on yoke?  Same thing if activated on a controller or keyboard?
Most likely need to see the top 1/3rd-ish of your DxDiag if available.
No custom sounds. Yes I was using onboard sound, sound max on a Asus motherboard, screwed the driver while trying to fix it and have not reinstalled it though But I am getting sound from my usb headphones, not sure whats going on there but it had no effect on the vox issue. And yes I tried re mapping it to the yoke and is still locked up, back to default key now.
DXDiag:
------------------
System Information
------------------
Time of this report: 12/28/2010, 19:58:52
       Machine name:
   Operating System: Windows XP Professional (5.1, Build 2600) Service Pack 3 (2600.xpsp_sp3_gdr.100427-1636)
           Language: English (Regional Setting: English)
System Manufacturer: System manufacturer
       System Model: System Product Name
               BIOS: BIOS Date: 08/14/06 17:01:53 Ver: 08.00.12
          Processor: Intel(R) Core(TM)2 CPU          6400  @ 2.13GHz (2 CPUs)
             Memory: 2046MB RAM
          Page File: 571MB used, 3367MB available
        Windows Dir: C:\WINDOWS
    DirectX Version: DirectX 9.0c (4.09.0000.0904)
DX Setup Parameters: Not found
     DxDiag Version: 5.03.2600.5512 32bit Unicode
------------
DxDiag Notes
------------
  DirectX Files Tab: No problems found.
      Display Tab 1: No problems found.
        Sound Tab 1: The file usbaudio.sys is not digitally signed, which means that it has not been tested by Microsoft's Windows Hardware Quality Labs (WHQL).  You may be able to get a WHQL logo'd driver from the hardware manufacturer.
        Sound Tab 2: The file ADIHdAud.sys is not digitally signed, which means that it has not been tested by Microsoft's Windows Hardware Quality Labs (WHQL).  You may be able to get a WHQL logo'd driver from the hardware manufacturer.
          Music Tab: No problems found.
          Input Tab: No problems found.
        Network Tab: No problems found.
--------------------
DirectX Debug Levels
--------------------
Direct3D:    0/4 (n/a)
DirectDraw:  0/4 (retail)
DirectInput: 0/5 (n/a)
DirectMusic: 0/5 (n/a)
DirectPlay:  0/9 (retail)
DirectSound: 0/5 (retail)
DirectShow:  0/6 (retail)
---------------
Display Devices
---------------
        Card name: NVIDIA GeForce 9500 GT
     Manufacturer: NVIDIA
        Chip type: GeForce 9500 GT
         DAC type: Integrated RAMDAC
       Device Key: Enum\PCI\VEN_10DE&DEV_0640&SUBSYS_0643196E&REV_A1
   Display Memory: 1024.0 MB
     Current Mode: 1920 x 1080 (32 bit) (60Hz)
          Monitor: Plug and Play Monitor
  Monitor Max Res: 1600,1200
      Driver Name: nv4_disp.dll
   Driver Version: 6.14.0012.5896 (English)
      DDI Version: 9 (or higher)
Driver Attributes: Final Retail
 Driver Date/Size: 7/10/2010 04:38:00, 6343040 bytes
      WHQL Logo'd: Yes
  WHQL Date Stamp: n/a
              VDD: n/a
         Mini VDD: nv4_mini.sys
    Mini VDD Date: 7/10/2010 04:38:00, 10604128 bytes
Device Identifier: {D7B71E3E-4500-11CF-D66D-4F2600C2CB35}
        Vendor ID: 0x10DE
        Device ID: 0x0640
        SubSys ID: 0x0643196E
      Revision ID: 0x00A1
      Revision ID: 0x00A1
      Video Accel: ModeMPEG2_C ModeMPEG2_D 
 Deinterlace Caps: {6CB69578-7617-4637-91E5-1C02DB810285}: Format(In/Out)=(YUY2,YUY2) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY DeinterlaceTech_PixelAdaptive 
                   {335AA36E-7884-43A4-9C91-7F87FAF3E37E}: Format(In/Out)=(YUY2,YUY2) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY DeinterlaceTech_BOBVerticalSt retch 
                   {6CB69578-7617-4637-91E5-1C02DB810285}: Format(In/Out)=(UYVY,YUY2) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY DeinterlaceTech_PixelAdaptive 
                   {335AA36E-7884-43A4-9C91-7F87FAF3E37E}: Format(In/Out)=(UYVY,YUY2) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY DeinterlaceTech_BOBVerticalSt retch 
                   {6CB69578-7617-4637-91E5-1C02DB810285}: Format(In/Out)=(YV12,0x3231564e) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY DeinterlaceTech_PixelAdaptive 
                   {335AA36E-7884-43A4-9C91-7F87FAF3E37E}: Format(In/Out)=(YV12,0x3231564e) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY DeinterlaceTech_BOBVerticalSt retch 
                   {6CB69578-7617-4637-91E5-1C02DB810285}: Format(In/Out)=(NV12,0x3231564e) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY DeinterlaceTech_PixelAdaptive 
                   {335AA36E-7884-43A4-9C91-7F87FAF3E37E}: Format(In/Out)=(NV12,0x3231564e) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY DeinterlaceTech_BOBVerticalSt retch 
         Registry: OK
     DDraw Status: Enabled
       D3D Status: Enabled
       AGP Status: Enabled
DDraw Test Result: Not run
 D3D7 Test Result: Not run
 D3D8 Test Result: Not run
 D3D9 Test Result: Not run
-------------
Sound Devices
-------------
            Description: Logitech H555 Headset
 Default Sound Playback: Yes
 Default Voice Playback: Yes
            Hardware ID: USB\Vid_046d&Pid_0a1b&Rev_0100&MI_00
        Manufacturer ID: 65535
             Product ID: 65535
                   Type: WDM
            Driver Name: usbaudio.sys
         Driver Version: 5.01.2600.5512 (English)
      Driver Attributes: Final Retail
            WHQL Logo'd: No
          Date and Size: 4/13/2008 10:45:12, 60032 bytes
            Other Files: 
        Driver Provider: Microsoft
         HW Accel Level: Standard
              Cap Flags: 0xF5F
    Min/Max Sample Rate: 100, 200000
Static/Strm HW Mix Bufs: 0, 0
 Static/Strm HW 3D Bufs: 0, 0
              HW Memory: 0
       Voice Management: No
 EAX(tm) 2.0 Listen/Src: No, No
   I3DL2(tm) Listen/Src: No, No
Sensaura(tm) ZoomFX(tm): No
               Registry: OK
      Sound Test Result: Not run
            Description: SoundMAX HD Audio
 Default Sound Playback: No
 Default Voice Playback: No
            Hardware ID: HDAUDIO\FUNC_01&VEN_11D4&DEV_1988&SUBSYS_104381E1&REV_1004
        Manufacturer ID: 65535
             Product ID: 65535
                   Type: WDM
            Driver Name: ADIHdAud.sys
         Driver Version: 5.10.0001.6240 (English)
      Driver Attributes: Final Retail
            WHQL Logo'd: No
          Date and Size: 5/18/2007 10:01:50, 304640 bytes
            Other Files: 
        Driver Provider: AnalogDevices
         HW Accel Level: Standard
              Cap Flags: 0xF5F
    Min/Max Sample Rate: 100, 192000
Static/Strm HW Mix Bufs: 33, 32
 Static/Strm HW 3D Bufs: 33, 32
              HW Memory: 0
       Voice Management: No
 EAX(tm) 2.0 Listen/Src: No, No
   I3DL2(tm) Listen/Src: No, No
Sensaura(tm) ZoomFX(tm): No
               Registry: OK
      Sound Test Result: Not run