1995 Pontiac Grand Am Car goes into reverse, drive, etc. Bu

Fluid is pretty clean. Not perfect but very slightly discolored and does not smell burnt. My check engine light comes on and goes off but not all the time.

Okay, so today its totally dead. No power at all. Turn the key and nothing. No power locks, radio, notta. And I did check the battery, which has a full charge and is working great. Any ideas now? Been told it may be something electrical that would explain both of these problems

A mechanic friend of mine checked all the fuses and he said they were all good. We pulled them one by one and still nothing. Its just dead. Had to be dragged onto a flatbed to take to my house. I think it may be beyond repair at this point, or at least not cost effective based on the value of the car. I think she decided to retire herself.

Battery was never dead, had full charge. The car itself has no power. When you turn the key. Nothing, not even a click, notta. My battery is fine and my alternator is getting power, just nothing else.

Would that explain both my power issue and my transmission issue? Or is it just my luck 2 things went wrong at once?

Is there any simple way to check this? Will it read on a diagnostic machine? My mechanic friend has a portable one.

How do I go about checking the switch? Where is it and how do I remove it? How do I test it once its out? Is it an expensive part?