Help icon on language bar and Computer icon on Alt + F4 dialog

[yutopon777]

As the title says, which system file has the resources for the help icon on the language bar, and the computer icon on the left side of the shutdown dialog when Alt + F4 is pressed? I checked some dll files that Windows often uses, but couldn't find them.
I wanna customize these to replace the XP icons, so I also wanna know where those icons are in XP. (I guess it's the same location)
I think this is a question that has hardly been raised but if anyone knows it, please let me know. Thanks.