"This is a difficult one. First, ZCFGSVC is actually essential to the proper functioning of many of the Intel ProSET utilities (but not all) and, as with most wireless adapters, whether from Intel or not, these System Tray ProSET utilities are a must if you are using your wireless connection, if only so you know when the signal is fading or dropping. Most importantly, part of the ProSET utilities are responsible for sending out the Wireless network name (SSID) that you need to connect to; so if you fully de‑install the ProSET utilities, you will not be able to connect to your wireless network. Thus, if you are using your wireless adapter, you should in principle keep this service and the ProSET utilities. The problem is that, in some PCs, ZCFGSVC can be incredibly badly behaved : taking up to 100% of CPU time and therefore resulting in an extremely slow PC, preventing the installation of software or Windows updates, or causing “Not Responding” or “End this Program” shutdown problems. If you experience this, try first the very latest drivers from Intel or your laptop manufacturer. If that still does not solve the problem and you have Windows XP/2003, try setting the “Wireless Zero Configuration” service to Disabled. If that still does not solve the problem, then try renaming the C:\Windows\System32\ZCfgSvc.exe file to ZCfgSvc.exe.old as ZCFGSVC is seemingly not necessary for the part of the ProSET utilities which enable you to connect to your wireless network."


from http://www.answersthatwork.com/Tasklist_pages/tasklist_z.htm