Grey screen apple logo prohibitory sign etc MacBook 2009 I have an older Mac book that will not boot. I have tried all key commands including fcsk which resulted in a "mach kernel" end result, so nothing worked. I don't have a system install disk (bought used). I would like to try a disk utility fix. I'm not sure if I need the specific install disk for the precise model, or if a generic Snow Leopard install disk will allow my to try to repair the disk. Or would the Snow Leopard  that came with my husbands later MacBook Pro work? Or do I need Disk Warrior 4? I will try to actually replace the hard drive if necessary but I would lose my data. This is my model: 

Apple MacBook 13-inch 2.13GHz Core 2 Duo (Mid 2009) MC240LL/A [Condition:Good][Memory:4GB (2x2GB PC2-6400)][Hard Drive:750GB Hard Disk Drive][Optical Drive:SuperDrive-DL
You can always just use your Snow Leopard installation discs, in order to reinstall OS X. If you can get on a copy of OS X El Capitan though, it would be better to have it installed on that Mac via a bootable USB.