Originally posted by Texicle
This should be what you're looking for:
Hope it helps.
That's quite complicated, but maybe you'll have to do it. If you use KDE, you can set it through Control Center under the keyboard settings. Probably on some other window managers too, like Gnome or whatever.
On the KDE desktop, click on the little wrench icon for Control Center modules. Then choose Peripherals then Keyboard. Then it says NumLock on KDE startup:
Choose the top one.