maybe i can use some help
 

so my 99 blazer will not turn on at all it will crank and crank but it just wont turn for some reason what can it be?? or what should I look for

Look to see if you're getting fuel, can you hear the fuel pump whine when you turn the key on? Last tune up? Plugs? You need fuel, air, and spark to run an engine.

just replaced all of that this past Monday except the wires, did replace the fuel filter and nothing theres times where I crank it and it wants to start but it wont like if shes not getting enough of something & have to check the fuel pump

Try squirting a little starting fluid in the intake, if it starts then its a fuel delivery problem.

thank I will do that as soon as possible & heres a lil video of what I exactly mean

Could b a fuel pump problem or an ignition module problem. What trouble-shooting codes r u getting?