Delete your preferences.xml file and restart the game.
If you have deleted the preferences.xml file and the issue still persists (the resolution is insufficient to display the game interface), with the game closed, edit the “preferences.xml”, that can be found by pressing 'Windows Key + R' and entering / %Appdata%/wargaming.net/WorldOfTanks
Note: You must have administrative permissions in order to successfully save any changed settings.
**It is highly recommended to copy this file into other location in case you need to recover it**
Open the "preferences.xml" file with the Notepad and press 'Ctrl + F' to Search the document. In the field that is provided, type “<windowedWidth>” and press enter on your keyboard or 'Find Next'.
The following commands can be modified:
<windowedWidth> 1920 </windowedWidth>
<windowedHeight> 1018 </windowedHeight>
<fullscreenWidth> 1024 </fullscreenWidth>
<fullscreenHeight> 768 </fullscreenHeight>
The game resolution can be also manually changed, by a different command on the preferences file:
Edit the middle number (XXXXXX) on the command: <aspectRatio> XXXXXX </aspectRatio>
Based on one of the following:
16:10 resolution (1440x900, 1920x1200, etc.) set it to 1.600000
16:9 resolution (1280, 720, 1920x1080, etc.) set it to 1.778000
4:3 resolution (1024x768, 1600x1200, etc.) set it to 1.333000
5:4 resolution, it’s weird.. But set it to 1.250000
Save the Notepad file, then right click on preferences.xml and select 'Preferences'. Next, check [Read-Only] at the bottom and accept.
You should now be able to start World of Tanks and the resolution settings you changed manually should be applied.