Nis.exe not running in task manager - virus?

On my Win7 laptop there seems to be no problem with NIS. Appears to download updates, appears to scan. Ran a Power Eraser and all checks OK. But nis.exe is not running in the task manager. The only Symantec or Norton process running is ccsvchst.exe *32 (Symantec Service Framework). When I first noticed this, I uninstalled and reinstalled NIS and for a period I saw nis.exe running but now it is gone.