I've had this same problem for a Couple Days too in 1997 Blazer. I'll go out and try to turn the thing on and it acts like the battery is dead, nothing will come on. I then can't get the key back out. Now I replaced the ignition switch like a month or so ago But the Battery isnt dead at all I can go back out it may start and it may not can someone please help me thanks

 

good tight connections at the battery?
Edit: I might get it load tested

 

*Moved to '2nd Gen Tech'*

 

Check your grounds, as well.
Also, check your starter... a lot of vehicles use the starter as something of a junction box.