You may have need to have accurate time on your Windows PC. Windows already does have support for network time server synchronization and with recent versions ti should be set and turned on by default meaning if PC has access to Internet it will synchronize its internal clock with some of the world atomic clocks.
However, it might be good enough as synchronization is set to rather infrequent time periods, one day or even whole week. For some purposes it is needed to have clock synchronized more frequently. I need it for working Amateur Radio digital modes.
There are number of third party applications that can be installed on Windows PC as SysTray applications or services and allow more precise time synchronization.
While looking for method to improve time synchronization without spneding additional resources, I found out that user can actually change time synchronization interval by himself by hacking though the Registry. Well I try to avoid hacking Registry until absolutely necessary.
So, I searched more and stumbled upon nice little tool Atomic Clock Sync. This tool is actually just configuration utility that sets Windows Time Synchronization Service. It does not take any resources as it is run only to set Windows itself.
And it is free. I mean truly free. no ads, no spamware, just plain simple free program. You do not even have to install it, all it takes is just download it and run.