Electrical problem
2001 Nissan Multi 4 cyl Automatic 82,000 miles

I bought this car in August to use for 7 months while living temporarily in Ireland. It is an 'Irish' Nissan which measn it was sold new in Ireland and is now used, versus being used in Japan and then shipped here to be sold as a used car. Anyway, it has been great until today. The motor wouldn't turn over. It sounded like it was trying but wouldn't turn. SO we had it towed, and then several hours later the mechanic called and said he started it and it ran fine, but turned it off for two hours and then it wouldn't start again. He thinks it could be "electronics' but isn't sure. Can you advise what it sounds like to you? If it is lectronics is that very expensive to fix? Thank you