Hello, @wilex.
To clarify, the oldest available QuickBooks Desktop is 2010, as the 2003 version is no longer accessible. However, you can consider installing the latest version to ensure smooth transactions for your business. I'm here to assist you with the process.
To begin with, please ensure that you have a backup file to restore your data.
Once you're ready, you can proceed with installing your chosen version of QuickBooks:
- From the Downloads & Updates page, select your product and version.
- If you don't know what version you use, see Not sure what version you use? Select Download.
- See How to Install QuickBooks Desktop ( for Windows) or check out this quick video.
After the installation, it's best to update QuickBooks Desktop to the latest release to avoid any program-related issues. You can follow the detailed steps outlined in this article: Update QuickBooks Desktop to the latest release.
If you have any further questions about managing your QuickBooks, please don't hesitate to reach out. We're here to help you anytime.