Are you on a network?
Did you enable "Everything"? (Browsing, NetBIOS Mgr, etc?)
svchost does all the "Services" (DHCP, DNS, etc), if you enable them...
Product: Windows
Company: Microsoft
File: svchost.exe
"Svchost.exe" (Generic Host Process for Win32 Services) is an integral part of Windows OS. It cannot be stopped or restarted manually. It manages 32-bit DLLs and other services. At startup, Svchost.exe checks the services portion of the registry to construct a list of services that it needs to load. In normal conditions multiple instances of Svchost.exe run at the same time. Each Svchost.exe session can contain a grouping of services, so that separate services can be run depending on how and where Svchost.exe is started. This allows for better control and debugging. More info More info
Note: The svchost.exe file is located in the C:\Windows\System32 folder. In other cases, svchost.exe is a virus, spyware, trojan or worm!
From MS:
support.microsoft.com/default.aspx?scid=kb;EN-US;314056ETA: Article on 100% CPU Usage:
irish.typepad.com/irisheyes/2004/03/svchostexe.html