System files may be deleted or corrupted due to errors in a software installation procedure or due to problems in the hard drive of the computer system. With corrupted or missing system files, the software may not start at all. System file checker is a utility available on the Windows XP operating system that analyzes the system files to determine if they have been corrupted. Corrupted or Missing system files can be repaired using the Windows installation CD. Choose the option to repair when prompted. No data will be lost during the repair process as only the original system files are copied.