"Day Light Savings Updates," in the Computer Related Discussion forum, begins: "The easiest solution is to go to Microsoft Windows Update and apply any updates.
Preparing for Daylight Saving Time changes ..."
If you have Windows 95, 98 or ME, the time zone editor version for you is listed on this page AXCEL216 / MDGx FREE ESSENTIAL System Components + Add-Ons The files you need are the tzedit.exe and (if you need it) the tzedit.hlp. (They are under the Windows 98 Resource Kit link.