Assuming you're in the US, sounds like you may have your language and/or keyboard set to US International instead of just US.  With an international layout, the quote key doubles as a way to add an accent to a vowel, which may explain why it behaves funny in normal typing.

I checked this with XP, but Vista is very similar:

1) Start - Control Panel - Regional and Language options

2) Click Languages tab

3) Click Details button

4) Check the listed keyboards.  If the only keyboard listed is US International, click "Add".   Set default input language to "English United States" and Keyboard Layout to US.   Click Apply, then OK.

5) Then under the Default input language set to English (United States) US, then Apply and OK.

6) If you don't need the other layout at all, use "Remove" to take it off, leaving just the US keyboard.

Alexandra thank you, thank you, thank you, thank you, thank you, thank you, thank you, thank you, thank you.:emotion-52:

I'm in Australia so I adapted your instructions for English Australia, and it works beautifully. My IT person has known about this problem for several months and the only option he could think of was to give me a new (as in different, but actually older & slower) computer.

Marion

Glad you got it sorted.  :emotion-1: