Windows XP? Easy to check.
Press Control-alt-Delete once (pressing more than once would reboot the computer). The Taks Manager will pop up, with several tabs available. Choose the "Performance" tab. A few graphs and numbers are visible, two are interesting:
- Physical Memory: Total. (number in KB, this will be slightly bigger than 1 million if you have 1 GB.)
- Commit Charge: Limit. (total amount of memory available, if it's more than 2 GB reducing the page file will be required).
On my system, there is 1 GB of RAM, and 512MB page file (commit charge limit of approx. 1.5 million). CAOTD works with that, when set to windows 95 compatibility mode and 256 colors.
If you want to adjust page file sizes, an explanation with pictures of the menus can be found here:
http://www.petri.co.il/pagefile_optimization.htm
Note that you may have to set it below the recommended limits to work with CAOTD. If you have more than 2GB of physical RAM, this method will not work.