Why does my netbook lag after 5 minutes of gameplay?

[d1ey0u]

Okay guys, recently I reformatted my laptop, and ever since I get serious lag after about 5 minutes of gameplay. These are the games I'm trying to play. They lag even on the lowest settings.

Darksiders II
Dungeon Defenders
Kingdoms of Amalur


I installed the same Win 7 I had before the reformat. Here are the specs on my netbook.

Code:

------------------
System Information
------------------
Time of this report: 9/12/2012, 12:19:53
       Machine name: POOTER-PC
   Operating System: Windows 7 Professional 64-bit (6.1, Build 7600) (7600.win7_gdr.100618-1621)
           Language: English (Regional Setting: English)
System Manufacturer: Hewlett-Packard
       System Model: HP Pavilion dv7 Notebook PC
               BIOS: Default System BIOS
          Processor: Intel(R) Core(TM) i5 CPU       M 460  @ 2.53GHz (4 CPUs), ~2.5GHz
             Memory: 6144MB RAM
Available OS Memory: 5942MB RAM
          Page File: 2471MB used, 9410MB available
        Windows Dir: C:\Windows
    DirectX Version: DirectX 11
DX Setup Parameters: Not found
   User DPI Setting: Using System DPI
System DPI Setting: 96 DPI (100 percent)
    DWM DPI Scaling: Disabled
     DxDiag Version: 6.01.7600.16385 32bit Unicode

------------
DxDiag Notes
------------
      Display Tab 1: No problems found.
        Sound Tab 1: 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: Intel(R) HD Graphics
       Manufacturer: Intel Corporation
          Chip type: Intel(R) HD Graphics (Core i5)
           DAC type: Internal
         Device Key: Enum\PCI\VEN_8086&DEV_0046&SUBSYS_144B103C&REV_02
     Display Memory: 1696 MB
   Dedicated Memory: 64 MB
      Shared Memory: 1632 MB
       Current Mode: 1600 x 900 (32 bit) (60Hz)
       Monitor Name: Generic PnP Monitor
      Monitor Model: unknown
         Monitor Id: CMO1711
        Native Mode: 1600 x 900(p) (60.008Hz)
        Output Type: Internal
        Driver Name: igdumd64.dll,igd10umd64.dll,igdumdx32,igd10umd32
Driver File Version: 8.15.0010.2189 (English)
     Driver Version: 8.15.10.2189
        DDI Version: 10
       Driver Model: WDDM 1.1
  Driver Attributes: Final Retail
   Driver Date/Size: 7/28/2010 14:10:34, 6547968 bytes
        WHQL Logo'd: n/a
    WHQL Date Stamp: n/a
  Device Identifier: {D7B78E66-4306-11CF-017B-4134A2C2C535}
          Vendor ID: 0x8086
          Device ID: 0x0046
          SubSys ID: 0x144B103C
        Revision ID: 0x0002
Driver Strong Name: oem7.inf:Intel.Mfg.NTamd64:iILKM0:8.15.10.2189:pci\ven_8086&dev_0046
     Rank Of Driver: 00E62001
        Video Accel: ModeMPEG2_A ModeMPEG2_C ModeWMV9_B ModeWMV9_C ModeVC1_B ModeVC1_C
   Deinterlace Caps: {BF752EF6-8CC4-457A-BE1B-08BD1CAEEE9F}: Format(In/Out)=(YUY2,YUY2) Frames(Prev/Fwd/Back)=(0,0,1) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY VideoProcess_AlphaBlend DeinterlaceTech_EdgeFiltering
                     {335AA36E-7884-43A4-9C91-7F87FAF3E37E}: Format(In/Out)=(YUY2,YUY2) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY VideoProcess_AlphaBlend DeinterlaceTech_BOBVerticalStretch
                     {5A54A0C9-C7EC-4BD9-8EDE-F3C75DC4393B}: Format(In/Out)=(YUY2,YUY2) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY VideoProcess_AlphaBlend
                     {BF752EF6-8CC4-457A-BE1B-08BD1CAEEE9F}: Format(In/Out)=(UYVY,YUY2) Frames(Prev/Fwd/Back)=(0,0,1) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY VideoProcess_AlphaBlend DeinterlaceTech_EdgeFiltering
                     {335AA36E-7884-43A4-9C91-7F87FAF3E37E}: Format(In/Out)=(UYVY,YUY2) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY VideoProcess_AlphaBlend DeinterlaceTech_BOBVerticalStretch
                     {5A54A0C9-C7EC-4BD9-8EDE-F3C75DC4393B}: Format(In/Out)=(UYVY,YUY2) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY VideoProcess_AlphaBlend
                     {BF752EF6-8CC4-457A-BE1B-08BD1CAEEE9F}: Format(In/Out)=(YV12,YUY2) Frames(Prev/Fwd/Back)=(0,0,1) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY VideoProcess_AlphaBlend DeinterlaceTech_EdgeFiltering
                     {335AA36E-7884-43A4-9C91-7F87FAF3E37E}: Format(In/Out)=(YV12,YUY2) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY VideoProcess_AlphaBlend DeinterlaceTech_BOBVerticalStretch
                     {5A54A0C9-C7EC-4BD9-8EDE-F3C75DC4393B}: Format(In/Out)=(YV12,YUY2) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY VideoProcess_AlphaBlend
                     {BF752EF6-8CC4-457A-BE1B-08BD1CAEEE9F}: Format(In/Out)=(NV12,YUY2) Frames(Prev/Fwd/Back)=(0,0,1) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY VideoProcess_AlphaBlend DeinterlaceTech_EdgeFiltering
                     {335AA36E-7884-43A4-9C91-7F87FAF3E37E}: Format(In/Out)=(NV12,YUY2) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY VideoProcess_AlphaBlend DeinterlaceTech_BOBVerticalStretch
                     {5A54A0C9-C7EC-4BD9-8EDE-F3C75DC4393B}: Format(In/Out)=(NV12,YUY2) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY VideoProcess_AlphaBlend
                     {BF752EF6-8CC4-457A-BE1B-08BD1CAEEE9F}: Format(In/Out)=(IMC1,YUY2) Frames(Prev/Fwd/Back)=(0,0,1) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY VideoProcess_AlphaBlend DeinterlaceTech_EdgeFiltering
                     {335AA36E-7884-43A4-9C91-7F87FAF3E37E}: Format(In/Out)=(IMC1,YUY2) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY VideoProcess_AlphaBlend DeinterlaceTech_BOBVerticalStretch
                     {5A54A0C9-C7EC-4BD9-8EDE-F3C75DC4393B}: Format(In/Out)=(IMC1,YUY2) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY VideoProcess_AlphaBlend
                     {BF752EF6-8CC4-457A-BE1B-08BD1CAEEE9F}: Format(In/Out)=(IMC2,YUY2) Frames(Prev/Fwd/Back)=(0,0,1) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY VideoProcess_AlphaBlend DeinterlaceTech_EdgeFiltering
                     {335AA36E-7884-43A4-9C91-7F87FAF3E37E}: Format(In/Out)=(IMC2,YUY2) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY VideoProcess_AlphaBlend DeinterlaceTech_BOBVerticalStretch
                     {5A54A0C9-C7EC-4BD9-8EDE-F3C75DC4393B}: Format(In/Out)=(IMC2,YUY2) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY VideoProcess_AlphaBlend
                     {BF752EF6-8CC4-457A-BE1B-08BD1CAEEE9F}: Format(In/Out)=(IMC3,YUY2) Frames(Prev/Fwd/Back)=(0,0,1) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY VideoProcess_AlphaBlend DeinterlaceTech_EdgeFiltering
                     {335AA36E-7884-43A4-9C91-7F87FAF3E37E}: Format(In/Out)=(IMC3,YUY2) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY VideoProcess_AlphaBlend DeinterlaceTech_BOBVerticalStretch
                     {5A54A0C9-C7EC-4BD9-8EDE-F3C75DC4393B}: Format(In/Out)=(IMC3,YUY2) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY VideoProcess_AlphaBlend
                     {BF752EF6-8CC4-457A-BE1B-08BD1CAEEE9F}: Format(In/Out)=(IMC4,YUY2) Frames(Prev/Fwd/Back)=(0,0,1) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY VideoProcess_AlphaBlend DeinterlaceTech_EdgeFiltering
                     {335AA36E-7884-43A4-9C91-7F87FAF3E37E}: Format(In/Out)=(IMC4,YUY2) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY VideoProcess_AlphaBlend DeinterlaceTech_BOBVerticalStretch
                     {5A54A0C9-C7EC-4BD9-8EDE-F3C75DC4393B}: Format(In/Out)=(IMC4,YUY2) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY VideoProcess_AlphaBlend
       D3D9 Overlay: Supported
            DXVA-HD: Supported
       DDraw Status: Enabled
         D3D Status: Enabled
         AGP Status: Enabled

Oh yea!
Im using Avast!, and I even put it in silent gaming mode before I play.

Please help me solve this problem. :/