Every time that I create a new form in my application, it uses the "Microsoft Sans Serif, 8.25pt" font by default. I'm not changing it because I know that in this case my form should pick up whatever the default font is for the system. However, when I run my application, the font that is used is still anything but Segoe UI (my default system font in my Windows Vista OS).
Why does this happen? How do I make sure that my application looks like a normal Windows application?
Check out this blog entry talking about the default font in Forms which leads to the problem you are experiencing and this Connect Bug with Microsoft's response. In short it just seems that Forms does not get the (correct) default windows font (which you have changed).