Vista - double char?

Hello everybody.
I just got my new laptop with vista 64 ultimate.
Very happy with it but I have an annoying problem now.
When I type a document some characters are giving me trobules:
e.g:
"
'
`
~

Basically what happens is:
I type my nice document including e.g. a characer '
for some reason the character is not written on screen the first time I press the key, but if I press the same key again it appears twice ''

I'm a bit confused, I guess this is something I can disable in Vista control panel. Any help?

Regards
rs232