Originally Posted by
resipsaloquitur
The original Earth-2 was merged with Earth-1, -S, -X, and -4 (I think) in COIE #10.
The Earth-2 that appeared after "52" was a near-identical recreation of the original Earth-2, but wasn't EXACTLY it. This is illustrated by the fact that Power Girl--a survivor of the original E2--traveled to the new version thinking she'd found her old home. Then she met the Power Girl who lived on that world and knew it wasn't it.
Think of it this way: imagine you owned a great Lego Space set as a kid, but you mixed all the pieces together with four other sets and couldn't remember how to take them apart again. You still have your classic blue Spaceman from that set, but now he's stuck playing with Batman and a bunch of other characters. Then one day, somebody brings you an original, unopened copy of your old Space set. Now your blue spaceman has a home! ...except the set you just got already had a blue spaceman, just like the original did. That's what happened to Power Girl.
The 2012 Earth-2 is like somebody took a bunch of modern Lego pieces and built an all-new Lego Space Set that kinda-sorta resembled your old set and even has the same name, but Steppenwolf showed up and killed three of the spacemen. It has a new blue spaceman who looks like the old one, but now he's gay. Also, you only got halfway through building the set before you quit because your older brother kept telling you to include more Batman in it, so you let someone else take over and it looks more like a Pirate ship instead.