I think this one is going to depend on your circumstances. Most likely you could argue enough to get it fixed, they will probably send it away and you'll be without a laptop for a couple or three weeks. If you paid $500 for it then you might struggle to get them to do it. If it was a $3000 model then I'd say you have a very good argument for getting it covered under the CGA, but it will depend on the store. There's also the risk they will claim you dropped it and not cover it.

But normally for me the conversation goes "I bought this from you a couple of years back, now it's not working". They say "Sorry it's out of warranty", I say "you're still required to fix it under the Consumer Guarantees Act". Then they get a manager and you repeat the conversation. They will normally agree at this point. If they say they can't do it without a receipt, tell them they have the record because the IRD requires them to keep the records for 7 years, and the GST Act requires they provide a copy receipt within 28 days of someone requesting it so please can I have a copy of my receipt?

Now, depending on how much $50 is worth to you and how much you like arguing with staff, it might just be easier to do it yourself.

Personally I have got a refund on a 2.5 year old laptop that died and a 2 year old phone that died, but I know some places are better about it than others.