I am on a 5200 fx also, 1.3 ghz celeron and 512 ram, at 1024x768 no aliasing get no lag.
lower the res and keep the qualty to mid-high quality in the setting in the game. You might wanna go back to the 61.77 drivers but then make sure you set the quality setting in the nividia control panel for high quaility or you lose some terrain features. Anti-aliasing lagged for me. With the newer drivers I had bugs at 2x also, the backgrounds "flash."
Otherwise have you checked your internet provider and....Are you running Spybot? Disable that program if you are using it. It totally interferes with GuildWars.
That's all i got...Cya in the game after release
