What can you do if a 1995 GMC Sonoma does not start even though it has spark and fuel and air and the fuel injector orings were recently replaced and the battery is fully charged?

I have the same problem, I check theinject spark and fuel on my 1997 GMC sonmoa And it still won't start check all the fuse's, then i check the timing chain and replace, Still no luck . I am hope someone will help us both.