My Bios Clock is not very stable, so i changed a parameter in my Registry.
Search in your Registry for:
HKEY_LOCAL_MACHINE/SYSTEM/ControlSet001/services/W32Time/NtpClient/SpecialPollInterval
I Changed the Parameter from 604800 ( 7 Days ) to 600 ( 10 Minutes).
So your Windows 7 Computer have alway the correct Time.
73 DL9ZU Michael