Go to the link and download the software:
https://osdn.net/projects/crystaldiskmark/downloads/77936/CrystalDiskMark8_0_4c.exe/
Run the setup and finish the installation.
You will get a window that looks like this once you open the software:
Click on ALL at the top right and that will run the speed test
Send me a picture of the results you get from running the test.