I got it kinda wrong in the original post, sorry. I'll give you a method that works now!
In the software for your keyboard, usually in the Control Panel, there should be an option to assign different programs to the hotkey buttons, so instead of getting IE when you press the button, you could set it to start Excel instead if you were so inclined.
If you find this option (I'm assuming it's there but that's a guess!) then you should be able to point the button at a shortcut you can make. To make the shortcut, open Windows Explorer and navigate to a folder out of the way that you're not going to delete stuff out of by accident, it should be fine in the root of C:
Right-click in a blank space in the right hand pane and choose New.... Shortcut. For the location, enter the following text:
"C:\Program Files\Internet Explorer\iexplore.exe" -new
Include all the " and don't forget the space before the -new.
Then go back to your keyboard software and point the Web hotkey at your newly made shortcut. It should now fire up a new occurance of IE every time it's pressed. Let me know if it doesn't.