[amsat-bb] PC clock

My PC's clock keeps getting off by enough to cause problems on near overhead passes. I've seen it off by more than 30 seconds. It is using Internet synchronization, which happens once a week. Is there a way to force Windows 7 to automatically update clock more frequently than once per week. Please don't tell me to monkey with the Windows Registry. I know PC clocks are notoriously inaccurate, but this is ridiculous.

Larry W7IN