Apparently, your computer is infected with the W32.Blaster.Worm or one of its variants.
This happened because you have not been using an internet connection firewall and have
neglected to install the critical updates available at the Windows Update website.
Are you looking for info about the cause of "Remote Procedure Call (RPC)",
initiated by NT Authority\System error message that shuts down Windows
(you might also see svchost.exe error occasionally)? http://www.faqs.org/rfcs/rfc1831.html
--
Carey Frisch
Microsoft MVP
Windows XP - Shell/User