when i want change a hard disk's icon, i will put an "Autorun.ini" file into the root dir of the disk, which content is:
[autorun]
icon=xxx.ico
that's just like change the icon of a CD
in Win98 and Win2000, it will take effect just after i saved the ini file and refresh the explorer; but in WinXP, it will take effect only after the system restart.