I've got MalwareBytes AntiMalware and AVG 8. I ran both scans individually and at the same time (just to see if I would freeze up, honestly...)
DXDIAG: (I've had this setup for about a year now)
------------------
System Information
------------------
Time of this report: 4/4/2009, 20:48:15
       Machine name: YOUR-CF92BC9618
   Operating System: Windows XP Professional (5.1, Build 2600) Service Pack 2 (2600.xpsp_sp2_gdr.050301-1519)
           Language: English (Regional Setting: English)
System Manufacturer: GATEWA
       System Model: GT5014                          
               BIOS: Default System BIOS
          Processor: Intel(R) Pentium(R) D CPU 2.80GHz (2 CPUs)
             Memory: 2046MB RAM
          Page File: 338MB used, 3599MB available
        Windows Dir: C:\WINDOWS
    DirectX Version: DirectX 9.0c (4.09.0000.0904)
DX Setup Parameters: Not found
     DxDiag Version: 5.03.2600.2180 32bit Unicode
------------
DxDiag Notes
------------
  DirectX Files Tab: No problems found.
      Display Tab 1: No problems found.
        Sound Tab 1: No problems found.
        Sound Tab 2: The file GPWADrv.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 8600 GTS
     Manufacturer: NVIDIA
        Chip type: GeForce 8600 GTS
         DAC type: Integrated RAMDAC
       Device Key: Enum\PCI\VEN_10DE&DEV_0400&SUBSYS_08911462&REV_A1
   Display Memory: 512.0 MB
     Current Mode: 1680 x 1050 (32 bit) (60Hz)
          Monitor: Plug and Play Monitor
  Monitor Max Res: 1600,1200
      Driver Name: nv4_disp.dll
   Driver Version: 6.14.0011.7516 (English)
      DDI Version: 9 (or higher)
Driver Attributes: Final Retail
 Driver Date/Size: 5/2/2008 21:46:00, 6108160 bytes
      WHQL Logo'd: Yes
  WHQL Date Stamp: n/a
              VDD: n/a
         Mini VDD: nv4_mini.sys
    Mini VDD Date: 5/2/2008 21:46:00, 6554496 bytes
Device Identifier: {D7B71E3E-4740-11CF-8E6A-9A2800C2CB35}
        Vendor ID: 0x10DE
        Device ID: 0x0400
        SubSys ID: 0x08911462
      Revision ID: 0x00A1
      Revision ID: 0x00A1
      Video Accel: ModeMPEG2_C ModeMPEG2_D ModeWMV9_B ModeWMV9_A 
 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: SigmaTel Audio
 Default Sound Playback: Yes
 Default Voice Playback: Yes
            Hardware ID: HDAUDIO\FUNC_01&VEN_8384&DEV_7680&SUBSYS_107B5049&REV_1032
        Manufacturer ID: 1
             Product ID: 100
                   Type: WDM
            Driver Name: sthda.sys
         Driver Version: 5.10.4618.0000 (English)
      Driver Attributes: Final Retail
            WHQL Logo'd: Yes
          Date and Size: 7/18/2005 20:40:40, 1019064 bytes
            Other Files: 
        Driver Provider: SigmaTel
         HW Accel Level: Full
              Cap Flags: 0xB5B
    Min/Max Sample Rate: 44100, 192000
Static/Strm HW Mix Bufs: 1, 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: GuitarPort
 Default Sound Playback: No
 Default Voice Playback: No
            Hardware ID: USB\Vid_0e41&Pid_4750&Rev_0001
        Manufacturer ID: 1
             Product ID: 100
                   Type: WDM
            Driver Name: GPWADrv.sys
         Driver Version: 3.00.0000.0004 (English)
      Driver Attributes: Final Retail
            WHQL Logo'd: No
          Date and Size: 7/26/2006 20:06:19, 417920 bytes
            Other Files: 
        Driver Provider: Line 6
         HW Accel Level: Full
              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