If you have already tried to reinstall, then all files may have been over-written, even though the install failed.

Just a note though. Microsoft doesn't do drivers and these have to be supplied for the OS to work properly. So any XP Setup disk or Vista Setup disk will not have the drivers you need. If this is some OEM machine, (like a Dell, HP, Acer, etc), then the manufacturer's web site may have the drivers for that operating system, for that make and model machine. So visit the manufacturer's web site and search there for the drivers. They may even have a page of help with installation procedures.

For example, with a Dell machine I would simply input the Service Tag number, (found on the bottom, back or sides of the case), into the Dell website and all the details and drivers and such for this machine will be displayed.

If this is self-built, then you're on your own and you will have to hunt down the drivers yourself, from each hardware manufacturer's web sites.