Random lag spikes in every game. Need help ASAP.

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System Information
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Time of this report: 4/25/2013, 22:06:23
Machine name: JACK-PC
Operating System: Windows 7 Professional 32-bit (6.1, Build 7601) Service Pack 1 (7601.win7sp1_gdr.130318-1533)
Language: English (Regional Setting: English)
System Manufacturer: MSI
System Model: MS-7309
BIOS: Default System BIOS
Processor: AMD Athlon(tm) 5000 Dual-Core Processor (2 CPUs), ~2.2GHz
Memory: 2048MB RAM
Available OS Memory: 2048MB RAM
Page File: 1988MB used, 2106MB 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
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Display Tab 1: No problems found.
Sound Tab 1: No problems found.
Sound Tab 2: No problems found.
Input Tab: No problems found.

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DirectX Debug Levels
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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)

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Display Devices
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Card name: NVIDIA GeForce 9500 GT
Manufacturer: NVIDIA
Chip type: GeForce 9500 GT
DAC type: Integrated RAMDAC
Device Key: Enum\PCI\VEN_10DE&DEV_0640&SUBSYS_133E1462&REV_A1
Display Memory: 1267 MB
Dedicated Memory: 499 MB
Shared Memory: 767 MB
Current Mode: 1600 x 900 (32 bit) (59Hz)
Monitor Name: Gateway HX2000
Monitor Model: HX2000
Monitor Id: GWY00CC
Native Mode: 1600 x 900(p) (59.946Hz)
Output Type: DVI
Driver Name: nvd3dum.dll,nvwgf2um.dll,nvwgf2um.dll
Driver File Version: 9.18.0013.1422 (English)
Driver Version: 9.18.13.1422
DDI Version: 10
Driver Model: WDDM 1.1
Driver Attributes: Final Retail
Driver Date/Size: 3/15/2013 01:46:27, 15042928 bytes
WHQL Logo'd: Yes
WHQL Date Stamp:
Device Identifier: {D7B71E3E-4500-11CF-5C72-33331CC2C435}
Vendor ID: 0x10DE
Device ID: 0x0640
SubSys ID: 0x133E1462
Revision ID: 0x00A1
Driver Strong Name: oem22.inf:NVIDIA_SetA_Devices.NTx86.6.1:Section011:9.18.13.1422ci\ven_10de&dev_0640
Rank Of Driver: 00E02001
Video Accel: ModeMPEG2_A ModeMPEG2_C ModeVC1_C ModeWMV9_C

It is old, but I've recently been playing Payday 2. It seems as if it started happening when I first played the beta in the beginning of August. I have it on mid-low settings, and at first, I didn't lag whatsoever. I can play with no log for about 5 minutes, then it'll lag for around 5 minutes. My fps will be around 30 and when the spikes start, it immediately drops to 0-2. I then tried to play TF2, same thing happened. I'd even get slight spikes on Minecraft.

I'm using AVG.

I'm just at a crossroads here because it just randomly started happening. I was having no problems at all one day, (didn't install or do anything to the computer) and the next day, BAM, lag spikes.