Installing Graphics Card Drivers?

I just completed a fresh install of Windows 7 Ultimate 32 Bit (x86) after formatting my computer, which was previously running Windows XP Professional SP3. Everything during the install went smoothly, but now I'm trying to install my graphics card drivers and it's not working. Before I go further, here are my system 'specs':OS: Windows 7 Ultimate 32 Bit Mobo: ASUS M2A-VM (Green) Graphics Card: nVidia 9800 GT CPU: AMD Athlon 5400+ The first driver I attempted to install was my motherboard driver. I used the CD that came with the mobo, but the drivers were not compatible with Windows 7 so I had to run the driver under compatibility mode for Windows Vista in order to open the setup, then I installed those drivers. I then restarted and attempted to install my graphics card drivers off the CD that came with my 9800 GT. The first set of drivers that it installed were the PhysX drivers and those installed just fine. It then attempted to install the actually graphics card drivers, but then it said "The NVIDIA Setup program could not locate any drivers that are compatible with your current hardware. Setup will now exit." I opened up dxdiag and checked under the display tab and it's not showing any hardware under that tab, as if I have no graphics card. I then tried installing the Windows 7 32 Bit drivers that I downloaded from the nVidia site for the 9800 GT but when it does the system compatibility check, and error occurs that says "NVIDIA Installer cannot continue, the graphics driver could not find compatible graphics hardware." I then checked in the device manager under the 'Sound, video, and game controllers' section and only Realtek High Definition Audio is there. I have also installed the drivers for my motherboard found on the ASUS website after selecting the Windows 7 OS. I downloaded and installed the driver under the 'Chipset' section titled 'AMD Chipset Driver V1.3.0.49 for Windows 7 32bit/64bit--(WHQL).'Basically, my computer is not even detecting that I have a graphics card yet my monitor is plugged into the DVI port on my graphics card, and my graphics card is on. Does anyone know what's going on? Better yet, does anyone know where I could find drivers that will work and make my system functional?EDIT: If anyone requires any further information in order to help me with my problem, just let me know and I will get it asap.EDIT2: I just looked in my device manager and I noticed that under the 'system devices' section there is a device with a exclamation point in a yellow triangle called 'PCI Standard PCI-to-PCI bridge'. There is another one with the same name that doesn't have the symbol. Could this perhaps be part of the problem? The error for this device is 'This device cannot find enough free resources that it can use. (Code 12) If you want to use this device, you will need to disable one of the other devices on this system.' I have a feeling this is the problem. I went into my bios and enabled the "Plug and Play OS" but when I did that it made my computer run INSANELY loud. So I turned it off.