Dead V5-561G, no sticker, SNID, S/N

I have a bad feeling I could be really hosed...
Less than a year ago, I scrimped and saved to buy my 12 yo a nice new laptop. Recently, it started randomly restarting. I know overheating can cause this, but that didnt seem to be the problem. Then the laptop just died altogether. Lights in front turn on, but nothing on screen. Still under warranty, so I go to ooen a case and...no sticker on the bottom, therefore cant determine SNID or S/N. Possibly my daughter removed it, not knowing it's important. I found a 22-digit number on the battery and entered that as the serial number, but that apparently isnt it. I have the receipt and packing list. I'm really hoping there's some way we can still take advantage of the warrantly, but I have no idea how...