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!
Power usage is a massive one for me. I go by £1/W/Year for consumption of always-on devices. (I think it's more like £3/W/Year now!)
If the 20w new server can do the same work as the 100w server, and will cost me less over 2 years including the purchase price, then the old server is obsolete.