Hello iv had the same problem and kinda fixed it.Just to be clear dunno if it will work 100% but you can give it a try.go to your system file find l2.exe right click and properties,then go to Compatibility-->Compatibility mode and check Run this program in compatibility mode for and choose windows 8 or 7.Then go down and check Disable fullscreen optimizations.If this works and for any reason client goes to full screen all will go small again.Also you will need a fresh l2files and not the ones that are already showing you small.I hope this helps you.