This doesn't exactly match your symptoms, but it might help. The
suggestion is to change the keyboard type from "United States - International" to "US".
http://www.bytesin.com/f25/windows-7-double-quotes-problem-pressing-2-times-have-effect-194.html
I had some similar, flaky behavior on the Windows 7 laptop. What
happened there, is I'm in Canada, and laptops here would be likely
to support both official languages. I don't have a problem with that,
except that Windows 7 would switch, all by itself, from one keyboard
layout option to another. Which caused one keyboard character to be
entirely wrong.
I fixed that, by changing so that only one keyboard layout option was
shown. So it had no choice, but to leave the damn keyboard alone.
I suspect your problem could be related.
When more than one keyboard layout option was available, I could
change the default to the correct value, but Windows 7 would change
it back again at random. I couldn't figure out what was going on.
The setting seemed to survive reboots, but perhaps half way
through a session, I'd start seeing garbage on the screen due
to the keyboard layout changing. Once I changed things so it only
had one option, that stopped the nonsense.
Paul