A nice HP laptop I was given by another kind Freegle user which had stopped working.
It is about 4 or 5 years old and nicely specified for running Linux Mint with 4 GB of ram and a fast multi-core Intel processor running at 2.2 GHz.
The guy's kids had been using it and it was covered in colourful stickers, which was cute, but it was also full of dust, probably because the kids had been sitting on the carpet to use the computer. This is really common and you see the same with Playstations and XBox consoles because they are usually put under the television on the floor.
The computer was reporting a fan failure which a bit of research turned out to be very common for this model. The fan sounded like it was on its last legs, so a full strip down was needed, then a serious clean out to remove all the dust and finally a replacement fan off eBay for about £4. The keyboard wasn't great so I got a new one of those as well for £7, total cost of parts £11. I carefully took all the stickers off and gave the laptop a good clean and it is pretty much as new.
Now running Linux Mint 18 (obviously) like lightening.