Try the following:
1. Set Internet Explorer to be your default browser, if it isn't already, via Program Access and Defaults from Control Panel.
2. Open IE and in Tools/Internet Options, verify that your language setting is correct for your country. (English - UK)
If it is not, click "Add" to select your language and country combination from the list.
Make that selection the default. It should appear at the top of the list.
Remove or demote other entries that are not appropriate for your country.
3. Delete cookies and temporary Internet Files from within IE.
4. On the IE connections tab, make sure "automatically detect" is not selected for the LAN settings.
5. Close IE.
6. Open OneCare and proceed with activation.
If the above still fails to bring you to the form for payment in your (supported) country, please contact support.
How to reach support (FAQ) - http://forums.microsoft.com/WindowsOneCare/ShowPost.aspx?PostID=2421771&SiteID=2
-steve
