Chosen Solution
A while a go my old MacBooks hard drive failed I wanted to upgrade it anyway so I bought a new 120gb ssd and a new hard drive cable (because the other one had a tear in it).When I hold option on startup it doesn’t detect the disk and when I go in disk utility from the OS X install disk it dosent detect it.
Sounds like you bought the wrong type of SSD. Your system only has a SATA II (3.0 Gb/s) interface so you do need to get a drive that is able to run at this slower I/O speed. As an example the Samsung 860 EVO SSD is able to run at this I/O speed. Here’s the spec sheet for reference Samsung 860 EVO SSD Spec sheet. You’ll note the ‘Interface’ line lists SATA II as supported. Make sure the SSD you bought states it otherwise its a fixed SATA III (6.0 Gb/s) drive which is what most are these days. You also want to install macOS 10.12.x Sierra as the best OS. While you can go up to 10.13.x High Sierra. I don’t recommend it as the newer APFS file system does not play well with SATA based drives.
