upon booting my Dell Demension E521 .. I see the dell startup screen with f-12 and f-2 commands in the top corner, neither choices work, then the Pheonix technoligies screen, after that it goes to a black n white load up screen in which it loads about 10% and then gives me this error:

Window could not start because the following file is corrupt or missing .. System/Drivers/pci.sys

You can attempt to repair this file by starting windows setup using the original set-up CD ROM...

Select 'r' at the first screen to start repair.

.... When I place the cd in I get the same actions as stated above.... Any suggestions?????