As standard, MetaTrader is installed under the Program Files folder, which is usually under the C: hard drive:

C:\Program Files\MetaTrader Folder\

Primary Path  Application Folder

Unless you have deliberately chosen a different location, the Primary Path

(C:\Program Files) will always remain constant. The only variation appears in the newer 64-bit (x64) versions of Windows where older, 32-bit applications such as MetaTrader 4 are installed into the “C:\Program Files (x32)” folder.

However, the Application Folder varies for every broker providing

MetaTrader 4. But don't worry - if you are not certain where your installation is located then there's a simple way to find out:

Position your mouse cursor directly over (do not click!) the icon on your Windows Desktop that you use to start MetaTrader 4...