Can't get HD3 back together again!

[luvsnwhd3]

Hi, I just bought a replacement battery from eBay. I'm having real trouble installing it though. I followed the instructions on how to dismantle the hd3 from the sony manual. Howver, upon pushing the system out of the case, there is a cable running from the case (the buttons (up down etc.)) to the system. This cable came udone as I was pulling the system out and before I realised it was there. I also had trouble putting the new battery in: is that silver back stuck to original battery (the bit that is screwed in) meant to go back in with the new? it doesn;t seem to fit, but the new battery does fit in without it. When I put the case back on I had trouble getting the bottom panel on properly. I managed to line up the hold and battery on/off switches, but where you plug the USB cable into the player, that part of the panel sticks out a bit. I should mention that even though it was sticking out, I charged the player up and it did work. I tried to put the cable that seemed to comeout of place earlier back to its original position. That must have worked. But... Because the panel was sticking out at the bottom, I pulled the system out again to see if it was something to do with the battery. Couldn't see anything. Now I'm worried the cable isn't back in properly, and the panel still won't stick down! I'm pulling my hair out. I'm sorry this is such a long post but I need your help!