All games are suddenly lagging :(

[Smilygod67]

Hey, ive had this new PC for about 3 months now and it ran great till now but all of a sudden all my games are lagging that worked a few days ago, any ideas why its doing this ? thanks in advance
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Time of this report: 7/2/2012, 00:35:27
Machine name: MATT-PC
Operating System: Windows 7 Home Premium 64-bit (6.1, Build 7601) Service Pack 1 (7601.win7sp1_gdr.120503-2030)
Language: English (Regional Setting: English)
System Manufacturer: Alienware
System Model: Alienware X51
BIOS: BIOS Date: 12/21/11 14:46:17 Ver: 04.06.05
Processor: Intel(R) Core(TM) i5-2320 CPU @ 3.00GHz (4 CPUs), ~3.0GHz
Memory: 8192MB RAM
Available OS Memory: 8086MB RAM
Page File: 3421MB used, 12750MB 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: 6.01.7601.17514 32bit Unicode

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DxDiag Notes
------------
Display Tab 1: No problems found.
Display Tab 2: No problems found.
Sound Tab 1: No problems found.
Sound Tab 2: 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 GT 545
Manufacturer: NVIDIA
Chip type: GeForce GT 545
DAC type: Integrated RAMDAC
Device Key: Enum\PCI\VEN_10DE&DEV_1241&SUBSYS_091D10DE&REV_A1
Display Memory: 4050 MB
Dedicated Memory: 978 MB
Shared Memory: 3072 MB
Current Mode: 1920 x 1200 (32 bit) (59Hz)
Monitor Name: Generic PnP Monitor
Monitor Model: NVD SIM DISP
Monitor Id: NVD0000
Native Mode: 1920 x 1200(p) (59.950Hz)
Output Type: HD15
Driver Name: nvd3dumx.dll,nvwgf2umx.dll,nvwgf2umx.dll,nvd3dum,nvwgf2um,nvwgf2um
Driver File Version: 8.17.0013.0142 (English)
Driver Version: 8.17.13.142
DDI Version: 11
Driver Model: WDDM 1.1
Driver Attributes: Final Retail
Driver Date/Size: 5/15/2012 04:48:00, 18044224 bytes
WHQL Logo'd: Yes
WHQL Date Stamp:

 

[hood6558]

What are your temps? I've had the same problem when the fan on the video card quit working, or was clogged with dust. I use OpenHardwareMonitor because it seems to read all the temps accurately and also shows loading info for the CPU and GPU.