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Service Host – Generic Host Process for Win32 Services. The full path to this file should be shown in The Ultimate Troubleshooter as C:\WinNT\System32\Svchost.exe or C:\Windows\System32\Svchost.exe. Windows 2000/XP/2003 only. SVCHOST is a generic process which acts as a host for processes that run from DLLs rather than EXEs. At startup SVCHOST checks the Services portion of the Registry to construct a list of DLL-based services that it needs to load, and then loads them. There can be many instances of SVCHOST running, as there will be one instance of SVCHOST for every DLL-based service or grouping of services (the grouping of services is determined by the programmers who wrote the services in question). Under Windows XP Professional and Windows 2003 you can find out what DLL-based services SVCHOST is running by typing Tasklist /SVC at a Command/MS‑DOS Prompt (this command is not available in Windows XP Home), while under Windows 2000 you need to use the TLIST –s command from a Command Prompt (MS-DOS Prompt) (depending on how Windows 2000 was installed you may need to download TLIST from the Microsoft website or install it from one of the miscellaneous folders on the Windows 2000 CD).
An integral part of the operating system, leave alone – multiple instances of SVCHOST is a normal occurrence. If you experience SVCHOST errors, the problem is most likely not with SVCHOST but with the DLLs it is hosting. However, if you experience a lot of SVCHOST errors, and particularly, if the full path to SVCHOST.EXE is not any of the above, then you most likely have a virus (see below).