90 Isuzu Trooper bad noise, then wouldn't start

My husband's Trooper has been an excellent car, but recently it has had a kind of grinding noise when running that was getting louder and definitely didn't sound good. Yesterday, he went to start it and it wouldn't start. The starter sounds like its trying, but isn't turning the engine, and there is plenty of power.

The Trooper has 6 cyl and about 125000 miles I believe. There is some dispute over the mileage tho. We bought used and the dealer selling it quoted it as having 135000 miles on it, but after we bought it we saw the odometer only said 35000, so I guess the dealer assumed that 1st # had to be a one since it was so old, so maybe we got a deal. Its never had any major mechanical problems in the 5+ years he's had it, not even a starter or alternator.

It is a manual drive of course, seems to be starter-related, something is no longer engaging. Both my husband and I are mechanically-inclined, but this has us put off a bit. Please help, sharing a car isn't fun! :( Thanks!