That was it! I must've changed that either by accident at some point, or sometime a while ago and not remembered. But either way, I went to the Runcommand menu and chose 'Remove video mode selection' and now it's working perfectly. Thanks!
Contributions to the project are always appreciated, so if you would like to support us with a donation you can do so here.
Hosting provided by Mythic-Beasts. See the Hosting Information page for more information.