I think you need a little more context. What do you mean by 'revisiting'? This is ambiguous. What were you revisiting and what does it have to do with your computer working or not? If I had to answer as it is, I'd say "wasn't working" is a safe choice. But I think you have to provide more context.
Well, your second version works much better than the first one, anaisss. 'Didn't work / wasn't working' both do not fit as they do not convey the change in the computer's performance - it worked and then stopped working. 'Crashed' does.
'Revising', I feel, also needs more context, at least what you were revising. 'I was studying' does not, it looks okay.