I cant get on my pc because it tells me windows could not start because the file is missing or corru

it says system32\drivers\pci.sys it was all right the other day its 3 years old and when i tried too put in the disc xp it does not work as its all scratched it tells me i will have to put in disc and press r at load up to repair it i tried it in safe mode and doe last good conf but no good can u help me get it running again as im not a computer whizz thanking you regards

I cant get on my pc because it tells me windows could not start because the file is missing or corrupt?antivirus download

Put xp install disk in at options screen choose repair windows leave file system as it is will restore to your original file system but leave your other files on the drive after install run your anti virus software to remove any viruses your system should be back to normal you can then put your up dates back on borrow an xp disk of a friend and re install as above

I cant get on my pc because it tells me windows could not start because the file is missing or corrupt?bmw

Do a scan disc, to see what the problem is. I had the very same problem a few months back. The error was due to corrupt files, I did manage to fix it eventually. But it meant me doing a recovery. And my advice if you are not too up on computers get help from someone who is. No doubt you will get more informed answers than mine. I do hope so good luck!
do an upgrade from your windows disk that way you will not lose any data
Try reinstalling Windows.