Again, like stated above, check to see if your motherboard has a slot for two kinds of ram.
I have a K7S5A and it only runs with one type of ram. You have to choose which, and DDR is better.
Check here for what windows detects:
(my laptop, this is the main page in system info)
I will also state that XP doesn't suck as bad as some of you claim. A computer is only as smart as the one using it. If yours sucks... well thats saying something :neutral:.
Mine rarely BSODs, but that might have something to do with what I do
Also, 256mb is enough for most people.
I have 512mb on my main comp and it is more then enough for my games, photoshop, web dev, and whatever else I decide to do.
Again, a Duron is slow, and most motherboards that support durons support athlon xp's (yours is kinda slow, so it might need an Athlon instead on an Athlon XP, sorry I'm not sure)
Anyways good luck
Mario