Visual Studio appears to randomly adopt American keyboard layout

Question

Gah! This is really causing me hassle today. Suddenly without warning \'@\' (at symbol) and \'\"\' (double quote) are trading places on my keyboard but ONLY in Visual Studio

Answer 1

I posted this on another question, but wanted to post the picture here in case you're not using XP, and want to see how to accomplish this in Windows 7: