I have a 2002 Chevy Trailblazer LS.

When I got the vehicle, it would simply decide not to start from time to time
as if the battery were completely dead. Then after a little while of turning
the key back and forth it would start like there was never an issue to begin
with. The security light was on on the dash board all the time so I assumed
it was the ignition lock cylinder. I changed it. The issue went away for about
two months but more often than not the key would lock itself in the ignition
when I would cut it off. I just got up this morning and it took four tries to
start it again. Once the engine was running I had not gauges, no radio, no
window power, nothing. It is like the vehicle does not know it is running. I
am very confused as to what could be causing this. Again, the security light
on the radio was blinking.
This is an intermittent issue. I turned the truck off, attempted a few more
times to start it again. Once running I had the same issue again. I repeated
the process one more time and now everything is running fine, however my
radio has reset itself as if the battery was disconnected. Anyone out there
able to give me educated advice on this? I can fix anything, but as far as
diagnosing electrical issues and computer issues I am lost.
Thanks Ya'll