Iam not a staff member here at geekstogo , however i may be able to assist you with your problem
there are two ways to solve the problem "Pci.sys Is Missing or Corrupt" Error Message When You Start Windows.
Booting with WinXP CD to access the Recovery Console’s Repair option, and then try to copy from WinXP CD the missing or damaged Pci.sys file to the systemdrive for your computer ( commonly C:\ )
Eg: C:\ (the computers hard drive) SO example of this would be C:\Windows\System32\drivers folder , then Exit and Reboot the computer
Hope i have not confused you
( If i have , dont hesitate to ask any questions )
try to Boot the computer with a Windows XP CD ( If available ) and then try to perform a Windows XP Repair Reinstall of the system currently installed on your machine
If you require any more detailed assistance please post with the details of your Operating system (WinXP Home or WinXP Pro and the SP ( Service pack ) i.e SP1 or SP2 or SP3 ) along with the manufacturer of your Computer as displayed on the computers case itself
These are only suggestions ( may not fix the problem ) , You may even have a faulty RAM stick... that can cause this error to occur
IF the above suggestions do not work and say you get a error " Setupdd.sys could not be loaded. Error code 4 " while attempting to start the windows Recovery console using the WinXP CD than you may have either incompatible PCI devices in the PCI slots or even one or several bad RAM modules installed ( or incorrectly fitted or even a faulty RAM module may be installed )
IF you suspect bad ram... Try removing one module at a time untill the faulty module is found... ( Only way to trouble shoot )
Remove one module ... reboot and see if the error message occours ( Untill the faulty module has been identified )
I hope this can help you concour the problem
Best of Luck!!! and happy computing !!!
PS: IF you do not feel comfortable removing the ram HAVE SOMONE ELSE HELP YOU !!! ( OR damage to the machine may occour )
PSS: Remember to EARTH yourself to the case ( as these modules are electrostatic sensitive )
And also do not wear clothes that may promote static electricity OR Floors Eg: Carpet ( Tiles would be preferable )
Once again, Best of luck!!!
Edited: Added more Detailed information
Edited by Anthony19, 18 November 2008 - 02:30 AM.