The BAD_SYSTEM_CONFIG_INFO bug check occurs if the SYSTEM hive is corrupt. However, this corruption is unlikely, because the boot loader, known as NT Loader (NTLDR) in versions of Windows prior to Vista, checks a hive for corruption when it loads the hive.
This bug check can also occur if some critical registry keys and values are missing. Thee keys and values might be missing if a user manually edited the registry.
Try restarting the computer by selecting "last known good configuration" in the boot options.
If the restart does not fix the problem, the registry damage is too extensive. You must reinstall the OS or use the Emergency Repair Disk (ERD) that you previously created by using the Windows Backup tool.