Smartdisk 160 gig not responding

Where to start....
Data recovery services are VERY expensive. One of the oldest and Best around is OnTrack.
They also offer a "do it yourself" data recovery software. Success rate is unknown.

Any external drive is simply a hard drive. In 20 yr's of doing computers, I've seen hard drives DOA, quit within 10 days of new, and others last 8 years, and suddenly give up the ghost one morning.

One thing you might want to try is removing the hard drive from the external enclosure, and putting it in as an internal slave drive in a computer. It's a "might work" at best. But if you can get it to spin up, pull that data off as quickly as you can (not all at once, little chunks at a time is better)

Just for a suggestion, if you can recover it, burn your data to CD's or DVD's. As long as you are using them on a daily basis, you have a much better chance at long term storage.
If you want to use it on a daily basis, burn multiple copies.

Any data that goes onto a computer is always at risk of being lost. That's where a non motorized / non electronic storage media is highly recommended.

Sorry I don't have any better suggestions, but being in the business, I have to be realistic about it, and don't want to build your hopes up too far.
Is there a chance of recovering it? Yes
What is that chance? I would say at best, maybe 20% chance of success.