I like the idea of the computer in a circle, but I agree with other posters that it isn't a perfect solution.
But what I don't get is why Harry doesn't put his shower in a circle. All he has to do is have the shower tray, or the water heater, in a circle and he gets hot showers. And if the circle goes, he doesn't lose data, or fry the hard drive the way he would with a computer. He'd probably just have to reset or change the fuse.
Unless, does the shower count as running water? Because it's stated that he'd need a stream to ground magic in the past, which is a bit bigger than the shower.
Even if it did, Molly could circle the heater while Harry was in the shower. That'd work. I think.