From the specs your SSD should be able to run in your system. Your systems SATA ports are SATA II (3.0 Gb/s) and your SanDisk SSD has auto SATA port sense technology so it can match the systems SATA port speed.
Using your HD to boot from see if you can check the systems firmware levels and if needed update it. Here's an Apple TN to help you: [https://support.apple.com/en-us/HT201518|About EFI and SMC firmware updates for Intel-based Mac computers]. You want to be at the listed level or newer.
Once you've check and if needed corrected the firmware. With the SSD installed plug in your HD using a SATA to USB adapter like this one: [https://www.startech.com/HDD/Adapters/USB-3-SATA-adapter-cable-with-UASP~USB3S2SAT3CB|Startech 2.5" SATA to USB adapter]. Then using pressing the Option key you'll be able to get to the Startup Manager (for reference: [https://support.apple.com/en-us/HT201255|Startup key combinations for Mac]) this will allow you to boot up under the HD are you then able to see the SSD on your desktop or using by Disk Utility from your HD?