Im having computer issues and i really need the info that is in my computer :( this is the problem (read)?

ok, when i turn the comuter on, it doesn't go to the loading windows screen. it says windows could not start because the following files are corrupt or missing: system32\drivers\pci.sys it says it needs repiar from the windows disc which i have. now my driver isnt opening!!! cmon, well i finally got it to open and the disk wasnt loading up at ALL it just kept saying the same thing. what should i do? cant get to desktop and F1 setup menu doenst do crap for me any help?