I am using eM on my main W10 PC, can I use this account on my W10 laptop as well please ?

Any help with the above would be greatly appreciated. I would like to use eM on my laptop as well as my main PC. (I am already using eM on the main PC) Any help would be greatly appreciated.

The license is per device.  Therefore, if you want to use it on 2 devices, you will need to get 2 licenses.  If you are not using it for business (or accessing more than 2 email accounts), you can get multiple free licenses by registering the product under a different email address.

Please note, however, that there is a significant discount for buying multiple Pro licenses at the same time.