Please help! 2004 Blazer 2wd 4 door V6. I turn the key, battery turns on, maybe an extra amount because for some reason it unlocked my back window, and it sputters a few times and will not crank up. The crank is a sputtering that makes all the dash lights blink while sputtering. It died a couple weeks ago in a parking lot, I watched a random youtube video and literally hit the top of the fuse box with my hand and it cranked up. Haven't had a problem again until tonight when it just will not turn over. I think trying so long may have run down battery because more I tried slower the car started and eventually stopped making the cranking sputtering. Do I need to replace the starter?

 

This likely will take some proper diagnosing. That hitting the fuse box might have helped suggests perhaps a bad ground or a bad fuse. Fuses can break mechanically rather than burn out due to over-current. For a quick check I'd look for some bad fuses.