Have Win 7 automatically check the time and set it

My PC is a tri-boot machine. It has Ubuntu Linux 8.10 on the primary hard drive and Windows 7 and XP on another. When it boots to the primary drive, Grub gives the user a choice between Linux or Windows. If you choose Linux, it goes straight into Ubuntu. If you choose Windows, then the boot gives you the choice of 7 or XP. It runs great. I did it this way because if I'm doing any intensive Windows hacking, I can just disconnect the Linux hard drive and then the boot choice is simply between 7 or XP without any hassles.

There's only one annoying bug to this setup. If I boot into Ubuntu, whenever I restart into either version of Windows, the clock is set 6 hours ahead of Central North American time where it should be. The time zone isn't changed. It's still set to Central Time. It's just 6 hours ahead.

I'd like to find a utility that I can put into the Windows startup forlder (or make run automatically on startup some other way) that will go online to see what time it is and then set my computer to whatever time it is, Central Time. Anyone know of anything?