Step 1. Scroll down the page a click the download button to download the English language pack for Autodata 3.40.

Step 2. While the language pack is downloading you will need to go to Autodata 3.40 installation directory, there is two ways of doing this, one is to right click the Autodata icon on your desktop and click open file location, or by going to C:\ ADCDA2 and double clicking the folder.

Step 3. We will rename the old language folder so we can go back to it if we want, to do this find the folder named ENG and right click it and select rename, then add .old to the end.

Step 4. Now go to the downloaded language pack and double click it and extract it to C:\ADCDA2.

Make sure that Autodata is closed before you try to rename or extract the new language pack.
Now run Autodata 3.40 and see if the language has changed to English, if it has you have successfully changed the language pack for Autodata 3.40.

http://www.gl-computers.co.uk/downloads/ENG.zip

Or
http://s15.alxa.net/001/001/Autodata.3.40.ENG.rar