you may want to try these:
(1) Change your desktop resolution to 1024x768 or a 4:3 compliant resolution
(2) Start LastChaos and Login. At the Character select screen click the Options button.
(3) Uncheck "Fullscreen" and click Ok, then Shutdown LastChaos
(4) Return to your native (normal) desktop resolution and then Restart LastChaos
(5) From the Otions Menu on the Character Select Screen, choose a 16:9 widescreen compliant resolution such as 1280x720, etc.
that was taken from the below link:
i just thought that might work or check the above link to check for more.