98 blazer 4.3 no start but cranks

will crank fine, but wont start. no lights in the dash cluster come on except the battery light. tried to jump start it with another vehicle but wont start. just replaced crank position sensor to stop the stalling problem.. does the computer have to be reset or something? anybody that can help it is appreciated.

With key to run without trying to start all the dsh warning lights should come on for like 5 sec - your do I take it but go out and only the battery light is on.
Cranks at a good speed but will not start - check the fuel pressure now and see if 60psi min key on engine off (start pressure) and it should not bleed down or drop more than a few lbs when the pump shuts off after initial prime. If thats good put a new cap/rotor on - Delco not a cheap one - they are having internal burn thrus/arching and it will show spark but fire in multiple cyls and never start.

the lights dont go on at all only the battery light.

Check your fuses in the main fuse panel with a 12V test light with the key on - almost all should have current on both sides on the top where the little bare wire is. Give special attention to the 20 and 30 amp fuses. Double check the ones labeled CPM, CPU, VCM or anything like that.