Radio won't function after battery 'disconnected'

I came back to my car when everything had been functioning fine and it would not start at all. On previous advice, I whacked the battery terminals. When I got back in all the gagues were flickering. The car started right up, but the radio will not turn on. There is no clock, no readout at all from the radio. Is this something I can fix myself?

What kind of car? Check all the fuses in the underhood and passenger compartment fuse blocks.Might want to get a meter and verify 12+ volts to the power center.

The car with the problem (I came back to my car when everything had been functioning fine and it would not start at all. On previous advice, I whacked the battery terminals. When I got back in all the gagues were flickering. The car started right up, but the radio will not turn on. There is no clock, no readout at all from the radio. Is this something I can fix myself?)
is a '03 Jeep Grand Cherokee.