Hi to everybody!!

I successfully installed Knoppipx on my hd, i made the necessary configs as root but.. when ilogged out to enter as different user... surprise !!!
The monitor received the "shutdown" signal!! So, instead of seeing the prompt where to choos with which user enter again. i have to reset the pc.

ANybody has some idea? do i have to change some video drivers?
My video card is a Radeon 7500, monitor nokia 447i.

thanks in advance!!