Yep, what Simon says. It's common on new laptops for the F keys to be reversed (ie: press for their alternate function, hold Fn + press for the F key itself). But indeed, you can usually change this in the BIOS.
If you can't change that setting on your PC, there isn't much that can be done for the main menu screen at this point; but for in-game, you could always remap the skill selection to different keys (open Config menu from the main menu, then select "Remap Hotkeys"); this requires V1.36n or higher (but of course, you should have V1.37n, or even better V1.38n, by now).