Ahh the old 'blue screen of death' No seriously that's what it's called!!
This occurs when Windows switches into kernel mode and a user-mode
subsystem, such as Winlogon or the Client Server Runtime Subsystem
(CSRSS), is compromised. Security can no longer be guaranteed. Because
Win XP can't run without Winlogon or CSRSS, this is one of the few
situations where the failure of a user-mode service can cause the system
to stop responding. This Stop message also can occur as a result of
malware infestation or when the computer is restarted after a system
administrator has modified permissions so that the SYSTEM account no
longer has adequate permissions to access system files and folders