Hello! My name is*****
I am a certified computer professional who will assist you with the problem you described.
The "2100: Detection error on HDD0" error refers to a problem with either the internal hard disk drive or the hard disk drive controller. Usually, changing the hard disk drive solves the problem. If your Lenovo laptop is still under warranty, you should contact the Lenovo support or an authorized Lenovo repair shop to report the problem and get it fixed.
However, in some cases, you can solve the problem by running both the memory test and the storage device (hard disk drive) test. If minor errors are detected, they will be automatically repaired. Here is how to run those tests:
1. Completely shut down the Lenovo laptop
2. Wait for 10 seconds and then power it back on
3. Immediately after pressing the power button, start pressing the F10 key several times
4. You will see the same "2100: Detection error on HDD0" error, but below it, it should also say "Press Esc to continue"
5. Press the Esc key and it should take you to the Lenovo Diagnostics screen. From there, you can run both tests
6. First, select Quick Memory Test and press Enter. It will take some time to finish. When finished, it should say PASSED
7. Press the Esc key to go back and now select Quick Storage Device test and press Enter. There select all options by pressing Enter on Select/deselect all if it isn't already automatically selected. It should then say [X] before all options. Now select Run Test and press Enter. Wait for it to finish. Once you see PASSED, the test has finished
8. Press the Esc key to go back and select Exit application and press Enter
9. The Lenovo laptop will restart. Do not press any key. In should now boot to Windows normally without the "2100: Detection error on HDD0" error
In case you have already tried with both tests, you can do it again. If it still doesn't work, then it means it is a hardware problem. Most likely, the hard disk drive has failed so you will need to take the laptop for a repair (have the hard disk drive replaced).
If there is anything else I can help you with, let me know.