pixel shader error?

dradym

for the last...many months, whenever i log in and patch, the game takes a millenium to load...only to error out and give me a pixel shader error, followed by a authentication error, but and able to relogin and play fine. my problem is that it literally takes 30 mins before i can play after every patch. it doesnt crash if i let it run til it errors and brings me to the login screen. after saying a pixel shader error in fine print at the bottom of the screen. if i log in after not having to patch, this doesnt happen, it all starts and runs just as i would expect.

as for my computer's specs, its running on vista home premium(32bit), with 3.4mhz dual core pentium, with 2gb ram, with ati radeon x1600. home built 5? years ago

its late, and im tired after an exhausting day, and not looking forward to the 30 min wait time tomorrow before i can play. thank you for any help