High battery voltage

[1slowdsm]

Alright, I'm lost again. I got a new alternator, switched it out and took the car for a spin around the block a few times. Now the stereo shuts off and comes back on every couple mins or so and when I park and turn the key into accessories I have no power, besides the usual dash lights, auto-belts dont work, stereo doesnt work. So I take the battery and have it tested at Checker Auto and it's still good. Now I dont know what else to think or check. Any more ideas? I dont wanna go driving and get stuck on the side of the road so I'm gonna recheck everything and hope I find something wrong.