Which screen resolution are you using? It has to be at least 1024 x 768 as far as I know. At least on the latest versions. That's also stated in the system requirements.
I don't have a recent edition of ACL, but that was my first thought as well.
If there is some reason you cannot keep your computer screen set at a compatible resolution for all programs, there is another option.
In Windows, you can create another "hardware profile". This means you will be able to boot up the computer with the hardware, such as video and sound cards, set to alternate settings to accommodate different software. You will have the option to choose between different profiles during the boot-up process.
Granted, it is a bit of an inconvenience at times, but if you only intend to run ACL during that session (and you should IMO) it may be worth the trouble.