My parents had an old but working MacBook 2012 that had a faulty hard disk drive. They replaced it but it say with me as it was a shame to chuck it- similar examples were selling for a couple of hundred pounds on eBay.
When lockdown hit again and we needed another computer to home school from, fixing this seemed ideal.
Reading online, the suggestion was to update the drive for a SSD one. I selected a budget 512GB one - most of our life is in the cloud these days. One thing to note is that a Mac specific drive is more expensive than a plain one - I just made sure the one I chose was the same size (I also went for a branded drive but still spent very little).
I decide not to increase the memory initially. I did remove it to check what it was and got the dreaded "three beeps" error. The video below helped sort that one out!
Once I had resolved this and cleaned the internals, I changed the drive and booted up the Mac. Nothing.
It's worth noting here that the Mac will usually try to restore online.
My Mac wanted to install an older version which stopped being updated 3 years ago. I knew that it had been running newer.
There are various key combinations to achieve a number of things when starting a Mac. They also depend on the machine you have. Eventually, this post helped.
After that it was plain sailing. The setup wizard worked well and we now have Teams, Skype, Chrome and the other apps needed to school all day.
I did buy some new feet for the Mac, at a princely sum of £1.49 as two had got lost. I will update the memory and battery in the future (I bought a new battery but rushed and got the wrong one. The international postage to return it was more than the battery so we will see if I can sell it on or give it away).
Let me know if this post helps you at all, or if you have any questions that you think I might answer.