In the OP situation this could play out like this:
1. Have a broken laptop (item #1)
2. Buy a new laptop (item #2)
3. Return item #1 with item #2's receipt
4. Have a working computer.
note: I'm not condoning this and it's unlikely to working in the OP's case because stores are usually smart enough to check serials on bigger ticket items.
Walmart has a very liberal return policy (accept anything) and the staff was somewhat aware this was going on. This is what my friend and former Walmart employee tald me years ago.
1. Buy item #1, obtain receipt, take it home
2. Go back into store, find identical item #2, take it past checkout counter and up to return counter
3. "Return" item #2 using receipt for item #1
4. Profit
For big ticket items there's usually a unique serial the store will scan to prevent this sort of thing, but not always. Pretty deplorable.