From UK Google to US Google

Hello,
I was in London in April and had my loptop with me, and of course looked things up on Google. But now that I'm back in the US, everytime I use Google it automatically goes to Google.co.uk, thinking I'm still in England! Does anyone know how to fix that? Someone said that it was because the clock on my computer had changed to a different time zone, but I never changed the time zone when I was there and it is still Pacific Time, as I live in California. I have Windows XP Media Center Version 2002 and I use Microsoft Internet Explorer. Many thanks.