Hi,
Because your CPU is only 700mhz, you'll probably need to turn the settings down a lot. The Mx440 is not strong, but it's ok. Your RAM is ok.
Make sure you don't enable antialiasing in the game or in the driver settings for the video card.
try 800x600x16 resolution if its still slow.
I don't understand why you only have a 700mhz Duron,
That mainboard is for XP CPU's at 333mhz Front side bus speed!!!! (ie. AMD XP2600+)


Mainboard: Asus P5K-Premium, CPU=Intel E6850 @ x8x450fsb 3.6ghz, RAM: 4gb PC8500 Team Dark, Video: NV8800GT, HDD: 2x1Tb Samsung F3 RAID-0 + 1Tb F3, PSU: Antec 550 Basiq, OS: Win7x64, Display: 24&