After hosting a game and alt-tabbing from the game, it didn't come up properly. Clicking buttons and keys worked, the sounds were all there, but the screen was grey.
 
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System Information
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Time of this report: 11/9/2008, 16:21:23
       Machine name: NERDMOBILE
   Operating System: Windows XP Professional (5.1, Build 2600) Service Pack 3 (2600.xpsp_sp3_gdr.080814-1236)
           Language: English (Regional Setting: Estonian)
System Manufacturer: INTELR
       System Model: AWRDACPI
               BIOS: Phoenix - AwardBIOS v6.00PG
          Processor: Intel(R) Pentium(R) 4 CPU 3.00GHz (2 CPUs)
             Memory: 1536MB RAM
          Page File: 817MB used, 2616MB 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
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DxDiag Notes
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  DirectX Files Tab: No problems found.
      Display Tab 1: No problems found.
        Sound Tab 1: No problems found.
          Music Tab: No problems found.
          Input Tab: No problems found.
        Network Tab: No problems found.
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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
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        Card name: GIGABYTE Radeon X1600 PRO
     Manufacturer: ATI Technologies Inc.
        Chip type: ATI Radeon Graphics Processor (0x71C2)
         DAC type: Internal DAC(400MHz)
       Device Key: Enum\PCI\VEN_1002&DEV_71C2&SUBSYS_21461458&REV_00
   Display Memory: 256.0 MB
     Current Mode: 1024 x 768 (32 bit) (85Hz)
          Monitor: Plug and Play Monitor
  Monitor Max Res: 1600,1200
      Driver Name: ati2dvag.dll
   Driver Version: 6.14.0010.6860 (English)
      DDI Version: 9 (or higher)
Driver Attributes: Final Retail
 Driver Date/Size: 8/21/2008 04:18:07, 314880 bytes
      WHQL Logo'd: n/a
  WHQL Date Stamp: n/a
              VDD: n/a
         Mini VDD: ati2mtag.sys
    Mini VDD Date: 8/21/2008 06:52:41, 3299840 bytes
Device Identifier: {D7B71EE2-3282-11CF-246D-4C01A1C2CB35}
        Vendor ID: 0x1002
        Device ID: 0x71C2
        SubSys ID: 0x21461458
      Revision ID: 0x0000
      Revision ID: 0x0000
      Video Accel: ModeMPEG2_C ModeMPEG2_D ModeWMV8_B ModeWMV8_A ModeWMV9_B ModeWMV9_A 
 Deinterlace Caps: {6E8329FF-B642-418B-BCF0-BCB6591E255F}: Format(In/Out) YUY2,YUY2) Frames(Prev/Fwd/Back)
YUY2,YUY2) Frames(Prev/Fwd/Back) 0,0,1) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY DeinterlaceTech_PixelAdaptive
0,0,1) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY DeinterlaceTech_PixelAdaptive 
                   {335AA36E-7884-43A4-9C91-7F87FAF3E37E}: Format(In/Out) YUY2,YUY2) Frames(Prev/Fwd/Back)
YUY2,YUY2) Frames(Prev/Fwd/Back) 0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY DeinterlaceTech_BOBVerticalStretch
0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY DeinterlaceTech_BOBVerticalStretch 
                   {3C5323C1-6FB7-44F5-9081-056BF2EE449D}: Format(In/Out) NV12,0x3231564e) Frames(Prev/Fwd/Back)
NV12,0x3231564e) Frames(Prev/Fwd/Back) 0,0,2) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY DeinterlaceTech_PixelAdaptive
0,0,2) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY DeinterlaceTech_PixelAdaptive 
                   {552C0DAD-CCBC-420B-83C8-74943CF9F1A6}: Format(In/Out) NV12,0x3231564e) Frames(Prev/Fwd/Back)
NV12,0x3231564e) Frames(Prev/Fwd/Back) 0,0,2) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY DeinterlaceTech_PixelAdaptive
0,0,2) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY DeinterlaceTech_PixelAdaptive 
                   {6E8329FF-B642-418B-BCF0-BCB6591E255F}: Format(In/Out) NV12,0x3231564e) Frames(Prev/Fwd/Back)
NV12,0x3231564e) Frames(Prev/Fwd/Back) 0,0,1) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY DeinterlaceTech_PixelAdaptive
0,0,1) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY DeinterlaceTech_PixelAdaptive 
                   {335AA36E-7884-43A4-9C91-7F87FAF3E37E}: Format(In/Out) NV12,0x3231564e) Frames(Prev/Fwd/Back)
NV12,0x3231564e) Frames(Prev/Fwd/Back) 0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY DeinterlaceTech_BOBVerticalStretch
0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY DeinterlaceTech_BOBVerticalStretch 
         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
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            Description: Realtek HD Audio rear output
 Default Sound Playback: Yes
 Default Voice Playback: Yes
            Hardware ID: HDAUDIO\FUNC_01&VEN_10EC&DEV_0880&SUBSYS_08800000&REV_0905
        Manufacturer ID: 1
             Product ID: 100
                   Type: WDM
            Driver Name: RtkHDAud.sys
         Driver Version: 5.10.0000.5172 (English)
      Driver Attributes: Final Retail
            WHQL Logo'd: n/a
          Date and Size: 9/23/2005 17:56:28, 3966976 bytes
            Other Files: 
        Driver Provider: Realtek Semiconductor Corp.
         HW Accel Level: Full
              Cap Flags: 0x0
    Min/Max Sample Rate: 0, 0
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: Yes, Yes
   I3DL2(tm) Listen/Src: Yes, Yes
Sensaura(tm) ZoomFX(tm): No
               Registry: OK
      Sound Test Result: Not run
---------------------
Sound Capture Devices
---------------------
            Description: Realtek HD Audio rear input
  Default Sound Capture: Yes
  Default Voice Capture: Yes
            Driver Name: RtkHDAud.sys
         Driver Version: 5.10.0000.5172 (English)
      Driver Attributes: Final Retail
          Date and Size: 9/23/2005 17:56:28, 3966976 bytes
              Cap Flags: 0x0
           Format Flags: 0x0
            Description: Realtek HD Digital input
  Default Sound Capture: No
  Default Voice Capture: No
            Driver Name: RtkHDAud.sys
         Driver Version: 5.10.0000.5172 (English)
      Driver Attributes: Final Retail
          Date and Size: 9/23/2005 17:56:28, 3966976 bytes
              Cap Flags: 0x0
           Format Flags: 0x0
            Description: Realtek HD Front Green Jack
  Default Sound Capture: No
  Default Voice Capture: No
            Driver Name: RtkHDAud.sys
         Driver Version: 5.10.0000.5172 (English)
      Driver Attributes: Final Retail
          Date and Size: 9/23/2005 17:56:28, 3966976 bytes
              Cap Flags: 0x0
           Format Flags: 0x0
            Description: Realtek HD Front Pink Jack
  Default Sound Capture: No
  Default Voice Capture: No
            Driver Name: RtkHDAud.sys
         Driver Version: 5.10.0000.5172 (English)
      Driver Attributes: Final Retail
          Date and Size: 9/23/2005 17:56:28, 3966976 bytes
              Cap Flags: 0x0
           Format Flags: 0x0
-----------
DirectMusic
-----------
        DLS Path: C:\WINDOWS\SYSTEM32\drivers\GM.DLS
     DLS Version: 1.00.0016.0002
    Acceleration: n/a
           Ports: Microsoft Synthesizer, Software (Not Kernel Mode), Output, DLS, Internal, Default Port
                  Microsoft MIDI Mapper [Emulated], Hardware (Not Kernel Mode), Output, No DLS, Internal
                  Microsoft GS Wavetable SW Synth [Emulated], Hardware (Not Kernel Mode), Output, No DLS, Internal
        Registry: OK
     Test Result: Not run