1972 Oldsmobile Delta 88 Royale

I recently purchased a 1972 Oldsmobile Delta 88 Royale. It has 78,000 miles on the original engine. Until recently, the car was running great. Last week it cutoff while my daughter was driving it. With a boost from my other car battery I was able to get it started and driven home. The following day it would not start, so I got the battery checked (OK) and charged. The car still will not turnover. No, it’s not out of gas (ha-ha). What do you think?

If I’m reading this correctly the vehicle died while moving? and you have no starter solenoid “click” sound when the key is turned to the START position.

Based on these symptoms this could point to a faulty ignition switch (electrical, not the key and tumbler) or a faulty fusible link. I’m assuming here that the battery cables are good and the battery was properly tested.
These cars are as simple as it gets and the problem should be very easy to diagnose.

Yes, the car was moving. No, I do not have a starter solenoid clicking sound when the key is turned to the START position. Yes, the battery cables are good and the battery was properly tested. Should I attempt to fix it myself or should I get a professional? Also, thank you.