Chaning a character in the keyboard

[Mr Dave]

Hi all, I am wondering if is possible to "change" a character in Windows. In particular, we often use the € char, but we have to push 2 keys ("Alt Gr" + E), but I would like to implement an application running in background (or even a windows service) that catches the key § (for example) and transforms it in € in every window application the user is working with. Do you think it is possible? Thanks in advance! Dave