W10 Day-Timer 2000 Program suddenly stops working

Hello and welcome to the forum! I'm sorry to hear that you're experiencing issues with your Day-Timer 2000 program on your Windows 11 desktop.
Based on the information you provided, it seems that the program is crashing with an exception code of 0xc000041d. This code usually indicates an application termination due to an unhandled exception.
Here are a few suggestions you can try to troubleshoot and resolve the issue:
1. Compatibility mode: Right-click on the dto2k.EXE file and select Properties. Go to the Compatibility tab and enable the "Run this program in compatibility mode for" option. Choose the appropriate operating system such as Windows XP or Windows 7, which the program previously ran on successfully. Click Apply and then try launching the program again.
2. Run as Administrator: While still in the Properties window, go to the Compatibility tab and check the "Run this program as an administrator" option. Click Apply and then try launching the program again.
3. Disable Data Execution Prevention (DEP): DEP is a security feature in Windows that can sometimes interfere with older applications. To disable DEP for the Day-Timer program, you will need to modify the system's advanced settings. To do this, follow these steps:
- Press Win + X and select System from the menu.
- In the System window, click on "Advanced system settings" on the left-hand side.
- In the System Properties window, go to the Advanced tab and click on the Settings button under the Performance section.
- In the Performance Options window, go to the Data Execution Prevention tab.
- Select the "Turn on DEP for all programs and services except those I select" option.
- Click on the Add button and navigate to the dto2k.EXE file in the Day-Timer installation folder.
- Select the file and click OK to add it to the DEP exception list.
- Click Apply, then OK, and try launching the program again.
4. Update or reinstall the program: Make sure you have the latest version of the Day-Timer 2000 program installed. Visit the developer's website or contact their support for any available updates or patches. If a newer version is not available, you may try uninstalling the program completely, rebooting your system, and then reinstalling it.
5. Check for system updates: Ensure that your Windows 11 desktop is up to date with the latest updates and patches. Sometimes, compatibility issues can arise with older applications if the operating system is not updated.
If none of the above suggestions work, it's possible that the Day-Timer 2000 program may not be compatible with Windows 11. In such cases, you could consider running the program in a virtual machine with a compatible operating system, or looking for alternative software that offers similar functionality and is compatible with Windows 11.
I hope these suggestions help resolve the issue and get your Day-Timer 2000 program up and running again. Let me know if you have any further questions or concerns!