it sounds like you've got your keyboard set to US not English, oer maybe theotehr way around. On a UK keyboard the @ is above the ', and the " is above 2. On a US keyboard it's reversed. I know this because I currently have a UK keyboard but a US setting (because my laptop is US so I like to stick to the one format and touch type).
If you want to change it you can click on the EN symbol on the very bottom right task bar. If UK english isn't an option you should be able to use this link to make it an option. At least, that's how you do it with Win2000 (what I'm working on at the moment).
I second the motion: sounds like a classic US keyboard setting when using a UK-style keyboard. If you can't get belgianfreak's method to work, try:
Control panel | Regional and Language options | Languages tab | Details button.
In there reside the controls as to what the PC thinks the keyboard is.