Extremely low fps at all times out of nowhere

Can you post the rest of your hardware config, thanks!

Operating System
Windows 7 ‎(X86)‎ Service Pack 1

Processor
AMD Sempron LE-1220 clocked at 2 GHz
Processor frequency measure (core0) : 2.01 GHz
Number of cores : 2 physical, 2 logical
Processor socket : Socket AM2 (940)
CPU Temperature (core 0) : 62.25 °C

Motherboard
ECS Nettle3 2.2
SKU Number : KT583AA#UUW
Bios version : 5.17
Date : 4/23/2008

Chipset
Northbridge : NVIDIA MCP61
Revision ID : A3
Southbridge : NVIDIA MCP61
Revision ID : A2

Memory
2 GB total memory type DDR2 to 402.71 MHz
Memory timing : 6.0-6-6-18-2T
Memory chip Qimonda from 1 GB
Maximum frequency : 400 MHz
Max bandwidth : PC2-6400
Memory chip Qimonda from 1 GB
Maximum frequency : 400 MHz
Max bandwidth : PC2-6400

Graphics card
NVIDIA GeForce 6150SE nForce 430
DirectX version installed : 11.0
Core clock : 425 MHz
Memory clock : 800 MHz

Harddrive
Harddrive Hitachi HDP725025GLA SCSI Disk Device from 232.88 GB
Harddrive Generic USB CF Reader USB Device
Harddrive Generic USB MS Reader USB Device
Harddrive Generic USB SD Reader USB Device
Harddrive Generic USB SM Reader USB Device

CD-ROM
Optiarc DVD RW AD-7201S5
Event type : DVD+R/DL Recorder
Firmware version : 1H0E

Network
NVIDIA Corporation MCP61 Ethernet
Adapter type : ethernet
Multimedia cards
NVIDIA Corporation MCP61 High Definition Audio

Can you think of anything, at all, that you did just prior to the drop in fps?

If you have system restore on try that ......providing you haven't done (too) much since your chosen point.

Perhaps your power supply is dying, thus your card is not getting enough power, or your card is dying?