Ubuntu affecting Windows XP clock

[Timothy Van Meir]

I have my machine set up to dual-boot Ubuntu and Windows XP Home
Edition.  Whenever I log out of Ubuntu and boot up Windows, the clock
is several hours ahead of the correct time (I think it's been
consistently 5 hours ahead, but I'm not sure of that).  It's easy to
reset the clock, but the problem recurs after each use of Ubuntu.

Any idea what might cause this, or how it might be fixed?

I'm in the US Central time zone, if that makes any difference.

Tim Van Meir