First of all tell me are you connected with other computer like on lan. If then svchost.exe will work there. Although it is an essential element for the Network. But the exe file is also reasonable for attacking by the blaster worm. Blaster worm attack the svchost.exe and also the rpc system. i think you know about the rpc shutdown as you are using windows xp you should know. And yes blaster worm also make attacks with svchost.exe For the solution read the following topic: http://www.nibbleguru.com/probs/100/399