ATI radeon 9800 problem

Hi

For some unknown reason my display has gone wonky throwing all wierd things up on my screen, dots, lines etc etc. thought at first it was my monitor on the way out but that checked out ok, so i thought i would install latest drivers for the said card.
But as soon as i start the installation i get the message:
Error installing ikernal.exe: the specified network name is no longer available

i even get this when i remove existing drivers & try to install old drivers from the supplied cd??????

Any ideas

many thanks