Trouble getting my new Geforce 9600GT working properly.. NEED HELP

Hello there everyone, i've been trying desperately and desperately to get my new rig to work so many times yet everytime I attempt to get it working ANOTHER problem seems to come up that makes me hate and have nothing to do with computers for weeks at times.. but im back and trying again.. so first i'll post my full computer specs.

CPU:
AMD Athlon 64 Dual Core 6000+ 3.11GHz

Memory:
Kingston DDR2 1GB

Power Supply:
(Unknown Brand) 520w 20pin

Motherboard:
Asus M2N-MX SE Plus

Videocard:
Nvidia Geforce 9600GT 1G

alright so i'll first start my story off by saying when I bought all these parts scratch new and got my friend to help me hook it up, we had a problem where the screen would just be blank as if no monitor were plugged in, long story short it turned out some of the memory from my old but still good PC didn't match up with my motherboard so we could only find 1 workable stick of RAM in the motherboard.. that required me taking it to a computer shop and them finding out about the faulty RAM... now I when I take my PC home and turn on Team Fortress 2 I notice this weirddd FPS lag and major spikes... to avail I find out now that my video card is messed or something is making my video card messed... I tried updating the Drivers to the current ones and reinstalling Windows and reinstalling the Videocard several times and still had the same effect.. my next thought was the powersupply.. now at first I had no idea what my regular power supply was (it's 520w) so I figured i'd go to my favorite computer shop and buy one thats decently priced and has a good amount of wattage I figured 550W should do it so I bought a brand new Coolermaster 550W 24Pin powersupply and was excited because I had finially thought I found out what was wrong with my computer.. plugged it in hooked everything up.. SAME PROBLEM.... now I was mad but it also got me thinking that maybe 550W is still way too little for my specs? thoughts? opinions? anyways let me explain in detail exactly what happens when I go into ANY game in ANY setting

A) join game

B) game usually starts off with about 80-120 FPS for 5-10 seconds

C) FPS will INSTANTLY spike down to 8-12 FPS and stay like that for a good 30-45 seconds

D) FPS goes back up to 80-120 FPS for 5-10 seconds

(repeat)

I will post all my BIOS information so you can examine and see if theres anything that would cause error that I could fix

ADVANCED ->
JumperFree Config ->
AI Overclocking [Auto]
Chipset Voltage [Auto]
Memory Voltage [Auto]

CPU Config ->
GART Error [Disabled]
Microcode Updation [Enabled]
Secure Virtual Machine Mode [Enabled]
Cool Quiet [Disabled]
ACPI SRAT Table [Enabled]

CHIPSET
NorthBridge -> Memory Config
Bank Interleaving [Disabled]
Channel Interleaving [Disabled]
Enable Clock to all DIMMs [Disabled]
MemCLK Tristate C3 [Disabled]
Memory Hole Remapping [Enabled]
DCT unganged Mode [Always]
Power Down [Enabled]

NorthBridge -> DRAM
Memory Clock Mode [Auto]

SouthBridge Config
Primary Graphics Adapter [PCIE -> PCI -> IGPI]
AZALIA Audio [Auto]
Front Panel [HD Audio]
Onboard LAN [Auto]
Onboard LAN Boot ROM [Disabled]
MCp61 HPET TABLE [Enabled]

Onboard Devices Config ->
Serial Port1 Address [3F8/IRQ4]
Port Address [378]
Port Mode [Normal]
Port IRQ [IRQ7]

PCIPnP
Plug And Play O/S [Yes]
PCI Latency Timer [64]
Allocate IRQ to PCI VGA [Yes]
Palette Snooping [Enabled]
IRQ-3-4-5-7-9-10-11-14-15 assigned to [PCI Device]

now can anyone out there please help me or offer any suggestions as to what might be giving me a hard time? thank you in advance!

 

I'm guessing your're using XP?, i know when i had slow down problems with games after setting up my brand new Athlon based computer, i had to download a driver for the Athlon CPU ,and that solved it.I dont know whether its the same for you though, but you could try it?

I know some games requird me to download this driver or get slow down problems.