hi friends!
i am very new to Linux type OS like ubuntu! i am in for 2 days!
but it seems that it is not as easy as windows os.

after ubuntu installed i tried to activate Desktop effect but an error occured so i blindly (as i dont know any thing about linux and ubuntu) followed some blog recipe for installing graphic driver on ubuntu. and after restarting it worked, desktop effect activated but there were some artifact like vertical line forms as i move the windows.
my Laptop is toshiba A60 with Ati radeon mobility 7000 AGP
i had several question:
1)how can i remove previous installed graphic driver?
2)how can i install ati radeon mobility 7000 driver on ubuntu 8.04?
i appreciate anyone who can answer me!