SVCHOST.EXE SYSTEM

IN WINDOWS XP PRO; UNDER TASK MANAGER / PROCESSES: I HAVE SVCHOST.EXE SYSTEM RUNNING. IF I RIGHT-CLICK ON THAT AND CHOOSE “END PROCESS”, ANOTHER WINDOWS POPS UP THAT LOOKS LIKE THE BLASTER VIRUS POPUP THAT STATES THAT THE SYSTEM WILL SHUT DOWN IN X NUMBER OF SECONDS. I HAVE RAN FROM SYMANTEC’S SITE A VIRUS CHECK AND I ALSO HAVE NORTON’S AV WITH UPDATED DEFINITONS THAT I ALWAYS KEEP UP TO DATE AND IT CANNOT FIND ANY INFECTED VIRUSES ON MY SYSTEM. ?????????
IS “SVCHOST.EXE SYSTEM” A VALID PROCESS THAT SHOULD RUN ON WINDOWS XP PRO?