RAM has decreased?

[Prof Pwnsworth]

I have 512Mb of DDR-RAM in my computer, PC 3200. I bought this comp in 2003. For a while BIOS told me that i have 512 Mb of RAM, and so did CPU-Z and so did various other programs. suddenly i only have 448Mb of RAM. I checked the RAM and their both sticks of 256Mb. So what the hell is happening? All i can think of is that maybe one of the SIMMs burnt out or something, should i replace it or will it last?

I guess if you need more stats on my comp:
AMD XP 3200+
2 80gb WDCs
Onboard Video, Geforce MX4000
Asus AN7 mobo
512? Mb or PC 3200 RAM, made by Infineon.

 

[Ku-sama]

"Onboard Video, Geforce MX4000"

onboard has started useing more memory, set it in your BIOS

 

[Prof Pwnsworth]

Right! i checked my bios, onboard was using memory. i feel very relieved. thanks alot

 

[Ku-sama]

yup