I am assuming the that OS is XP, in which case go to:
1)Control panel
2)Regional and language settings
Under the regional options page it should say "English(United Kingdom)"......... if it doesn't then use the drop down menu and select it, being careful not to select the "English(United States)" instead.
Then click on "Languages" then "details".........
The default language should be "English (United Kingdom"...... if it is not click on "add" then under the "input language" scroll down until you get to "English (United Kingdom)".....select that.
The keyboard layout part should say "US"
Click OK etc and then restart your computer.
Hope that works
Regards
FBW