pci.sys is corrupted or missing

I was having 20gb drive and I replaced it with 160gb and installed Windows on it. It worked properly, but I downloaded a bad driver and so wanted to do a system restore. So, when I ran the system restore and went to far, so I reversed the system restore. But at the time of reversing I got an error that said "some file could not be recovered on C:.. or something". So, I tried to restart the computer and it said pci.sys is corrupt or missing and to run the recovery console. When I inserted the Windows setup disk to run recovery console, it started to load files for the setup and then I got a message that said pci.sys is corrupted or missing. Now I am stumped over here and cant do anything. So can anyone tell me how to solve this issue? Thanks.

Even I am having similar issue. I have bought a new har drive and also getting the PCI.SYS stop error after the installation is done and windows begins to start. It seems to me that there is some kind of hardware issue. I also removed the original drive and installed it in another pc and it booted up. Please help.

It looks to me that it is a bad ram in your machine, you can try to test each ram stick by downloading the Memtest86+ tool on its official website.

Check the article on "Windows XP problems with damaged or incompatible hardware" from here - http://support.microsoft.com/?kbid=330181