ok i'm not sure if this is where i should be posting this but.... i run windows xp and i have gotten this message several times and would like to know if anyone can tell me what it means exactly ....

this system is shutting down. please save all work in progress and log off. any unsaved changes will be lost. this shutdown was initiated by NT AUTHORITY\SYSTEM


time before shutdown : then it counts down the seconds

message
windows must now restart because the remote procedure call (rpc) service terminated unexpectedly.


i'm not sure why it did this.
thank you for your help