create registry key for system restore (if missing)

this describes how to create registry key for system restore in windows xp.

• go to the registry editor
• go to the key of HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WindowsNT\CurrentVersion\SystemRestore
• then go to the Edit menu, select New, DWORD
  value,
• rename it as '' DisableSR ''
• now set the value to 1 to disable System Restore or 0 to enable System Restore