So far I have solved most of the problems on my own system by adding COUNTRY=002,,C:\DOS\COUNTRY.SYS in config.sys (US keyboard)
and modifying the International section of Windows 3.1 (or WFW 3.11) setup to use YMD, Century date on, leading zero day, leading zero month, separator minus (-). 24 hour mode Time. And I downloaded the patch for Filemanager.
For Win 95, Win 98 and NT Regional settings, enter yyyy-MM-dd as the date mask, '-' as the separator, HH:mm:ss as the Time mask. Each user must define these regional settings.
And I have a plan for my BIOS tickover. The first time I use my machine in 2000, I will type in the date using the DATE command (in a DOS window) and supply a four-digit year. This fixes even so-called "non-compliant" hardware. Just do it. I also use the free SLUG2000 date scanner available from Cinderella, just in case.
Configure and use full 4 digit years in applications and observe the results of their interactions. Old form date inputs and displays are OK (cosmetic) if internal binary dates are used and produce correct results. (See the Cinderella Acceptability Index). Replace programs that do not comply.