Enable the Network Analyst License, this should "light up" the Network Analyst Tool Bar. Load Facilities into your service area by R-click and choosing a point FC/Shapefile to be your facilities. Facilities need not be snapped to a road network but a search distance to the network can be specified. Without Facilities you cannot "Solve" for Service Areas. If you have no options in your Network Dataset drop-down then you have no valid Network Dataset loaded.
... View more