To make your machine always be aware of the correct time, you best make use of the NTP protocol. On our department, there is a NTP server (ntp.cs.kuleuven.be) where you can ask for the correct time using that protocol.

You find more information about this protocol on these pages.

For Windows NT (4.0), there is a time service included in the Resource Kit. The files to install timeserv on your Windows NT machine can be found here.
Read the guide lines in the .wri file and check the configuration in the .ini file before trying to install.