I'm having similar issues, here is my dxdiag.
(as a side note, should I update my sound driver?)
------------------
System Information
------------------
Time of this report: 8/26/2009, 23:59:20
       Machine name: STEVEN-PC
   Operating System: Windows Vista™ Home Premium (6.0, Build 6001) Service Pack 1 (6001.vistasp1_gdr.090302-1506)
           Language: English (Regional Setting: English)
System Manufacturer: OEM
       System Model: OEM
               BIOS: Phoenix - AwardBIOS v6.00PG
          Processor: Intel(R) Core(TM) i7 CPU         920  @ 2.67GHz (2 CPUs), ~3.2GHz
             Memory: 2038MB RAM
          Page File: 595MB used, 3722MB available
        Windows Dir: C:\Windows
    DirectX Version: DirectX 10
DX Setup Parameters: Not found
     DxDiag Version: 6.00.6001.18000 32bit Unicode
------------
DxDiag Notes
------------
      Display Tab 1: No problems found.
        Sound Tab 1: No problems found.
        Sound Tab 2: No problems found.
        Sound Tab 3: No problems found.
          Input Tab: No problems found.
--------------------
DirectX Debug Levels
--------------------
Direct3D:    0/4 (retail)
DirectDraw:  0/4 (retail)
DirectInput: 0/5 (retail)
DirectMusic: 0/5 (retail)
DirectPlay:  0/9 (retail)
DirectSound: 0/5 (retail)
DirectShow:  0/6 (retail)
---------------
Display Devices
---------------
        Card name: NVIDIA GeForce GTX 260
     Manufacturer: NVIDIA
        Chip type: GeForce GTX 260
         DAC type: Integrated RAMDAC
       Device Key: Enum\PCI\VEN_10DE&DEV_05E2&SUBSYS_12573842&REV_A1
   Display Memory: 1646 MB
 Dedicated Memory: 883 MB
    Shared Memory: 763 MB
     Current Mode: 1920 x 1200 (32 bit) (60Hz)
          Monitor: SyncMaster 2433BW/2433GW,SyncMaster Magic CX2433BW/CX2433GW(Digital)
      Driver Name: nvd3dum.dll,nvwgf2um.dll,nvwgf2um.dll
   Driver Version: 8.15.0011.9038 (English)
      DDI Version: 10
Driver Attributes: Final Retail
 Driver Date/Size: 7/14/2009 14:54:00, 7565824 bytes
      WHQL Logo'd: n/a
  WHQL Date Stamp: n/a
Device Identifier: {D7B71E3E-46A2-11CF-BC78-5C3201C2C535}
        Vendor ID: 0x10DE
        Device ID: 0x05E2
        SubSys ID: 0x12573842
      Revision ID: 0x00A1
      Revision ID: 0x00A1
      Video Accel: ModeMPEG2_A ModeMPEG2_C ModeVC1_C ModeWMV9_C 
 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 
                   {F9F19DA5-3B09-4B2F-9D89-C64753E3EAAB}: Format(In/Out)=(YUY2,YUY2) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY 
                   {5A54A0C9-C7EC-4BD9-8EDE-F3C75DC4393B}: Format(In/Out)=(YUY2,YUY2) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY 
                   {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,UYVY) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY DeinterlaceTech_PixelAdaptive 
                   {F9F19DA5-3B09-4B2F-9D89-C64753E3EAAB}: Format(In/Out)=(UYVY,UYVY) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY 
                   {5A54A0C9-C7EC-4BD9-8EDE-F3C75DC4393B}: Format(In/Out)=(UYVY,UYVY) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY 
                   {335AA36E-7884-43A4-9C91-7F87FAF3E37E}: Format(In/Out)=(UYVY,UYVY) 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)=(YV12,0x32315659) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY DeinterlaceTech_PixelAdaptive 
                   {F9F19DA5-3B09-4B2F-9D89-C64753E3EAAB}: Format(In/Out)=(YV12,0x32315659) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY 
                   {5A54A0C9-C7EC-4BD9-8EDE-F3C75DC4393B}: Format(In/Out)=(YV12,0x32315659) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY 
                   {335AA36E-7884-43A4-9C91-7F87FAF3E37E}: Format(In/Out)=(YV12,0x32315659) 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 
                   {F9F19DA5-3B09-4B2F-9D89-C64753E3EAAB}: Format(In/Out)=(NV12,0x3231564e) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY 
                   {5A54A0C9-C7EC-4BD9-8EDE-F3C75DC4393B}: Format(In/Out)=(NV12,0x3231564e) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY 
                   {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 
                   {6CB69578-7617-4637-91E5-1C02DB810285}: Format(In/Out)=(IMC1,UNKNOWN) Frames(Prev/Fwd/Back)=(0,0,0) Caps=
                   {F9F19DA5-3B09-4B2F-9D89-C64753E3EAAB}: Format(In/Out)=(IMC1,UNKNOWN) Frames(Prev/Fwd/Back)=(0,0,0) Caps=
                   {5A54A0C9-C7EC-4BD9-8EDE-F3C75DC4393B}: Format(In/Out)=(IMC1,UNKNOWN) Frames(Prev/Fwd/Back)=(0,0,0) Caps=
                   {335AA36E-7884-43A4-9C91-7F87FAF3E37E}: Format(In/Out)=(IMC1,UNKNOWN) Frames(Prev/Fwd/Back)=(0,0,0) Caps=
                   {6CB69578-7617-4637-91E5-1C02DB810285}: Format(In/Out)=(IMC2,UNKNOWN) Frames(Prev/Fwd/Back)=(0,0,0) Caps=
                   {F9F19DA5-3B09-4B2F-9D89-C64753E3EAAB}: Format(In/Out)=(IMC2,UNKNOWN) Frames(Prev/Fwd/Back)=(0,0,0) Caps=
                   {5A54A0C9-C7EC-4BD9-8EDE-F3C75DC4393B}: Format(In/Out)=(IMC2,UNKNOWN) Frames(Prev/Fwd/Back)=(0,0,0) Caps=
                   {335AA36E-7884-43A4-9C91-7F87FAF3E37E}: Format(In/Out)=(IMC2,UNKNOWN) Frames(Prev/Fwd/Back)=(0,0,0) Caps=
                   {6CB69578-7617-4637-91E5-1C02DB810285}: Format(In/Out)=(IMC3,UNKNOWN) Frames(Prev/Fwd/Back)=(0,0,0) Caps=
                   {F9F19DA5-3B09-4B2F-9D89-C64753E3EAAB}: Format(In/Out)=(IMC3,UNKNOWN) Frames(Prev/Fwd/Back)=(0,0,0) Caps=
                   {5A54A0C9-C7EC-4BD9-8EDE-F3C75DC4393B}: Format(In/Out)=(IMC3,UNKNOWN) Frames(Prev/Fwd/Back)=(0,0,0) Caps=
                   {335AA36E-7884-43A4-9C91-7F87FAF3E37E}: Format(In/Out)=(IMC3,UNKNOWN) Frames(Prev/Fwd/Back)=(0,0,0) Caps=
                   {6CB69578-7617-4637-91E5-1C02DB810285}: Format(In/Out)=(IMC4,UNKNOWN) Frames(Prev/Fwd/Back)=(0,0,0) Caps=
                   {F9F19DA5-3B09-4B2F-9D89-C64753E3EAAB}: Format(In/Out)=(IMC4,UNKNOWN) Frames(Prev/Fwd/Back)=(0,0,0) Caps=
                   {5A54A0C9-C7EC-4BD9-8EDE-F3C75DC4393B}: Format(In/Out)=(IMC4,UNKNOWN) Frames(Prev/Fwd/Back)=(0,0,0) Caps=
                   {335AA36E-7884-43A4-9C91-7F87FAF3E37E}: Format(In/Out)=(IMC4,UNKNOWN) Frames(Prev/Fwd/Back)=(0,0,0) Caps=
                   {6CB69578-7617-4637-91E5-1C02DB810285}: Format(In/Out)=(S340,UNKNOWN) Frames(Prev/Fwd/Back)=(0,0,0) Caps=
                   {F9F19DA5-3B09-4B2F-9D89-C64753E3EAAB}: Format(In/Out)=(S340,UNKNOWN) Frames(Prev/Fwd/Back)=(0,0,0) Caps=
                   {5A54A0C9-C7EC-4BD9-8EDE-F3C75DC4393B}: Format(In/Out)=(S340,UNKNOWN) Frames(Prev/Fwd/Back)=(0,0,0) Caps=
                   {335AA36E-7884-43A4-9C91-7F87FAF3E37E}: Format(In/Out)=(S340,UNKNOWN) Frames(Prev/Fwd/Back)=(0,0,0) Caps=
                   {6CB69578-7617-4637-91E5-1C02DB810285}: Format(In/Out)=(S342,UNKNOWN) Frames(Prev/Fwd/Back)=(0,0,0) Caps=
                   {F9F19DA5-3B09-4B2F-9D89-C64753E3EAAB}: Format(In/Out)=(S342,UNKNOWN) Frames(Prev/Fwd/Back)=(0,0,0) Caps=
                   {5A54A0C9-C7EC-4BD9-8EDE-F3C75DC4393B}: Format(In/Out)=(S342,UNKNOWN) Frames(Prev/Fwd/Back)=(0,0,0) Caps=
                   {335AA36E-7884-43A4-9C91-7F87FAF3E37E}: Format(In/Out)=(S342,UNKNOWN) Frames(Prev/Fwd/Back)=(0,0,0) Caps=
     DDraw Status: Enabled
       D3D Status: Enabled
       AGP Status: Enabled