93 S10 Blazer starter drag / no start

Use a digital multimeter across battery posts, everything off, 12.6 volts is the generic spec for a full charge. If battery is down, get a charger and get it charged up. Make sure battery connections are all good. Again, you can leave meter leads touching battery posts and have helper crank it, the reading shouldn't drop below 9.6 volts or about there. If the reading is way down, that won't work. Make sure battery is good and fully charged. Did you try jumper cables or a jump box to get it started? In the past, I've seen ignition timing so far off, that the starter would drag. Once I reset the timing the starter was all good. good luck with your testing.

just to add, if battery is down, check your charging system.