Yep, one of the oldest scams in the book. Take it from another fellow transcriptionist.. It is a scam. All payments go through Upwork. No checks for software. Report it and move on
It definitely seems fishy! When I have encountered responses that sound iffy, I usually thank them and end communication.
Nothing about that interaction falls within the Upwork guidelines, so even if it's a "legitimate" offer, you are both in violation of the terms of Upwork. Try to keep your communication and transactions on this site. In addition to keeping your account in good standing, you'll have additional protection to ensure you get paid, and a record of all of your jobs and interactions with clients (or potential clients).
Steer clear! Keep applying for projects that have more in-depth descriptions. It's hard to pass up an offer that seems lucrative, but even if you end up getting paid, it's often not worth the hassle of dealing with those clients.
I'm sorry to learn about your experience with this client. As others have noted, this is a known scam, and I would recommend that you flag the client's job post so that actions can be taken against the client and his job post.
I would recommend that you read up on these freelancer resources and these tips for avoiding questionable jobs, for help getting started, and for more information about working safely through Upwork.