I just tested this in Chrome on my PC, which is the same spec as yours. But I didn’t run into any issues with the download. Just to make sure I’m trying the same action, are you attempting to download Microthemer from My Downloads on themeover.com?
If you were trying to use the email download link, it shouldn’t make your browser crash, but the links do expire after a while. And so I’ve emailed you a new download link.
It’s getting pretty late here in the UK, but I’ll check back on this first thing tomorrow if you’re still stuck.