I just bought a new HDD for my PS3 because my old one was full. So I didn't have a big enough eternal drive (only had a 8 GB USB) so all I did was take all my movies, songs and game saves and put it on the USB drive, I didn't put any 'Game Data' files on it.

I have the new HDD in and I put in all the games I own and re downloaded and installed them all to get all the 'Game Data' back, but for some reason the save for my Fallout 3 and GTAIV is missing (I'm pretty sure they were both the Autosave files), my main one that I put a lot of hours in, I have other ones but they are all like 30 hours behind my main save. So I'd like to be able to access my old PS3 hard drive to see if I missed something or what?

So could I just take out my new hard drive and put the old one back in and check everything then put the new one back in once I get the save file, or is there another way.

Also will I have to reformat the HDD everytime I pop one in or does that only happen with new HDD?

Some things aren't copied when you back your PS3 up.

Try copying them manually.

No that's what I did, I copied everything manually. I didn't have enough space (I needed atleast a 30 GB HDD or USB stick and I only have a 8 GB USB) so I just copied everything manually to my usb stick, I was positive I copied all my saves.

Try again then.

Certain game saves can't be copied. I know that Burnout Paradise and Resident Evil 5 are 2.

Thats sucks if you lose fallout.

I copied my RE5 save games when I had to send my PS3 in for no longer reading discs..

Did it work after being copied back onto your PS3's HDD?? 

The thing I'd like to know is, if I take out my new HDD and put the old one back in will the PS3 ask to reformat the old drive? or will everything work the way it should.

^ Yes u will need to reformat