I think it's your keyboard setting that needs to be changed.
If so go to the "start" menu, to "control panel", and then select "Regional and Language" option.
In the window that opens up select the second tab "Languages" and then select 'Details'. This takes you to the keyboard settings and you should be able to select English (United Kingdom). This should be in bold and then press ok.
start->control panel
choose regional and language options
on the languages tab select details button
change your input language to english/united kingdom.
Sounds to me like your keyboard settings may have gone on a bit of a US holiday trip
You need to reset to GB keyboard by going to control panel (in classic view), selecting Regional and language options and setting regional options to English (United Kingdom) that hopefully should bring things up ok.
Apparently in XP, software can change the keyboard layout to suit itself, problems may arise when said software is shutdown without changing back the layout.