Nope; Putting your 'old' HDD into a new system will only have you to reformat the drive. Thus losing all your files.
So backing it up while you still can, is the only way to get your files.
Nope. The hard drive is encrypted, even if you plugged it into a PC it wouldn't be able to read the old drive. Each hard drive is married to each PS3, because each PS3 has it's own encryption key that it uses to encrypt the entire drive. That's why your old drive wouldn't work in your new PS3.
So...yeah, I know it's a bummer, but you'll never see your old data again.
Nope, Sony made the great decision for auto encryption. It's showing how much of a pain it is recently, with more and more PS3's breaking, including mine.
This is what I have told a few Sony reps on the phone the last few weeks and they say that Sony doesn't really give a rat's ass about our game data.