If the 'About Windows' dialog is not displaying complete information, ensure your Windows is up to date by checking for updates in 'Settings > Update & Security > Windows Update'. If the issue persists, using alternative methods such as the 'System Information' tool can provide comprehensive details about your Windows version, build number, and other system specifics. If discrepancies continue, it may indicate a system or licensing issue, in which case contacting Microsoft Support for assistance would be advisable.