Hmm it’s quite subtle. Didn’t is a simple statement of fact. Wouldn’t implies it’s refused to start.

"didn't" is the negative auxiliary for the Past, whereas "wouldn't" is for Conditional sentences and for Future in the Past. They mean basically the same thing in this context though.

Hi Mehdrad, As the others have pointed out, the 2 sentences mean the same thing. Out of context, the 2 sentences seem equally likely... but they really aren't. 'Would' is more likely to be used in writing or more formal spoken situations. 'Did' is more common in casual, everyday spoken conversation. Informal spoken conversation tends to be really quick and easy... people choose simple verbs, like 'did', and express shades of meaning in tone of voice and body language. I hope this helps! :)