Default [Q] Archos 40 titanium Can anyone figure out what happened?

I would rather have a better explanation (if there is a better one) then what I'm about to say as I'm planning on returning the phone and getting something else.

I went to unlock the phone, but upon pressing the power button instead of being presented with the lock screen, I heard the sound the phone usually makes when the phone is locked/unlocked and after that the phone wouldn't respond to the power button and the volume buttons would only light up the 'buttons' underneath the screen, so I pulled out the battery which did clear the problem but the battery charge had dropped to 52% from around 90% (in the battery use details for Android OS the keep awake details shows a duration of 2h 14m 37s which might be something to do with this problem as I don't think I've seen that part show any duration since I got it which is only a few weeks) and a few minutes later it stopped responding to the power button when locked again (which has prompted my returning the phone to where I got it from since I can't trust it to be reliable now).

Something else I need to ask is about backing up data for specific apps I've been using (none of which should have caused this problem to happen) as restoring data for one of them is likely to be a pain to do.
Can I just transfer the apps to the SD card (which I already have in the phone, and does contain some data for one of the apps) and put the SD card into the new phone when I get it, or is it going to be more complicated?