While moving from one nest to another (we're lemmings here; RP it a bit) I realized I still have all computers I ever bought or assembled, except for those that literally broke beyond any hope of repair.
Some are no longer used daily but all work and being on a point in life where everything and anything in the nest needs to have a purpose or a function, led me think what actually renders a computer useless or truly obsolete.
I was made even more aware of this, as I'm in the market to assemble a new machine and I'm seeing used ones - 3 or 4 years old - being sold at what can be considered store price, with specs capable of running newly released games.
Meanwhile, I'm looking at two LGA 775 motherboards I have and considering how hard can I push it before it spontaneously combusts to make any use of it, even if only a type writer.
So, per the title, what makes a computer obsolete or simply unusable to you?
Addition
So I felt necessary to update the post and list the main reasons surfacing for rendering a machine obsolete/unusable
overall and consumption vs computational power
Linux rule!
I would say when it becomes too slow for even basic tasks like browsing the web, or running an up-to-date operating system.
Today, I would say the bar is around 3000-4000 points on cpubenchmark for the cpu, 8gb of ram and an SSD.
You could definitely get a usable computer that has less. I have a Pentium II PC that works great, and can even connect to the Internet. But software today is far more bloated and inefficient than it used to be, such an old machine would be useful only if you don't do anything computationally intensive, and don't need to run any modern software.
But something I forgot to mention about old hardware is that it allows you to run old software, old games... and there's also the nostalgia of Windows XP, or Windows 98, the early web. They remind me of a simpler time...