Windows 10, it's a desktop, and my screen resolution is 1024x768
At last, the web version does work but it runs terribly, at a frame rate so low that is absolutely unplayable
I see. Probably the computer specs are a bit low for the game.
You should seriously consider getting a newer PC. That's a 15 year old processor you're using there. Pretty cool that it still works to this day, but it may be a bit slow for comfortable gaming. A dedicated GPU will help a lot too. If you don't plan to game often, just get the low spec ones and it should be fine.