You could try this
post Postby mithion » Mar 28th, '13
assuming it is just X that is messed up, do a normal boot and get to a Console with
( or F2,3,4.. )
from there you should be able to reconfigure the drivers following mithion's guide.
I would be tempted to jump right in and run the drakx11 the text version of the graphics driver configuration tool
if that fails, do the full guide.