That doesn't sound very good , if it's making a new wierd sound and crashing, that would make me think that your cooling fan is not attached properly and your CPU is shutting down when it simply gets too hot.
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If I were you, I'd get an iPad and try it out before I bought a new laptop. I think it will do almost everything you want to do, but faster, easier and more securely. And it will be so much easier to carry around the house. If you are worried about learning something new, don't sweat it, everything is very intuitive.
You could keep your old laptop for stuff that's not great on the iPad after taking it back to the repair 🤡 clowns and making them get rid of the noise.
I agree that the new weird noise preceding the crash is worrying. It's likely one of two things: the fan, as jimbocz has said, which could be fixed to prevent any more overheating and solve your problem; or the hard drive (assuming you don't have a SSD, which is silent), which is
very bad, and it's good that you just backed up all your stuff.
As for an iPad (or other tablet) in place of a laptop... I had a second-hand iPad from an old friend, and it had its uses (for example, my husband and I did a photo shoot for a restaurant and we wirelessly sent photos to the iPad for previewing on a bigger screen than our camera's LCD offered). Also, you can get a keyboard with your tablet, so you have the tactile typing option, too, and the 'keyboard' won't take up 1/3 of your display area.
But for me, a tablet would feel too confining, and I do a lot more with my does-it-all laptop that a tablet can't do. But it could be the option for you. I would compare the costs of the tablet (plus keyboard) and laptop, and go with whatever is more economical.