Clock is setting to a Different Time Zone

Hi All,

I installed Vista (Dual Boot along with XP). now when I selected Central
Time Zone (I am in Chicago), it is showing me +2 Hrs in general (Central Time
Zone + 2Hrs). I tried to change it, but of no use.

Now I booted with XP and tried to do the same, it is still showing +2 Hrs.
Eventhough I am trying to change, it is not changing and showing me +2 Hrs of
current time.

Not sure how to escape from Time Monster. Can anyone help

Thanks in Advance.