Computer Help

I need some help guys. I built my first computer a couple of weeks ago and everything works fine, but i am having trouble with my hard drive capacity not being fully recognized. I bought a western digital 640gb HDD but i am only showing 137gb. I've tried looking for help on the internet but i can't find the solution. It seems it's a common problem for older motherboards or something, but i'm sure i've used updated parts. I tried different jumper settings but nothing seems to work. I also tried downloading the intel application accelerator but it said my chipset is not compatible.

Here are the parts i used:
HDD - Western Digital Caviar WD6400AAKS 640GB 7200 RPM
Mobo - ASUS RAMPAGE FORMULA LGA 775 Intel X48 ATX Intel
CPU - Intel Core 2 Duo E8400 Wolfdale 3.0GHz
OS - Microsoft XP Pro (i already downloaded SP3)

thanks

 

I used the XP Pro CD i got while i was a student. I don't think it's a recovery CD. I've already started using it and it works perfectly fine. I used NTFS to format. I hope i didn't miss something while i was installing the OS. If i redo my partition, will i lose everything i've installed (drivers, software)? This was my first build so i was expecting problems like this. The only other thing wrong is the USB hubs in front of the case don't work even though it's plugged in on the Mobo. I appreciate all the help!

 

It's new. I bought it from newegg but it didn't come in a box, it was just wrapped up and thrown in with the other parts. It didn't have any instructions or jumpers.