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!
It's all very arbitrary and depends on the definition of computer for the individual.
Ultimately it does, I think, come down to practicality. Can I still use this thing to get what I need to do done, and can I still do it securely?
The security part can be more or less important depending on computer, as well. If you're a Mac person, your machine may be obsolete as soon as Apple decides to stop giving you security updates. If you're a Linux person, you can probably maintain a secure system easily on 10-15 year old hardware.