Only 85% dead

My computer is pretty much dead. Yesterday when I tried to start it up the screen wouldn't work properly, like everything was jumbled up.
Today I tried plugging a monitor into it to see if that worked, and both screens worked fine for a while ...

... but then both screens stopped working.
So either way, I'm going to have to get a new computer. I have a couple of options for how to get a decent secondhand computer but if anyone has any other ideas, please let me know.