Comment 1 for bug 878025

> Every other program I use on my W7 system can do this correctly

Did you actually compare it with other applications using the GTK+ toolkit (e.g. GIMP) on Windows?

In Inkscape (like e.g. in GIMP), the standard keyboard shortcut <F10> [1] activates the main menu: this keyboard shortcut is also listed in the 'Inkscape keyboard and mouse reference':
<http://inkscape.org/doc/keys048.html#d0e1244>

Individual menus are accessed with 'Alt' + access key (underline character in the menu name) [2].

[1] <http://developer.gnome.org/hig-book/2.32/input-keyboard.html.en#widget-navigation>
[2] <http://library.gnome.org/users/user-guide/2.32/shortcuts-access.html.en>