What would happen if I replaced the Windows XP SHELL32.dll with the Windows 2000 SP3 SHELL32.dll. This seems to be where all the icons are kept - would this change my icons from the terribly ...

The only way that I could come up with changing icons showing in items such as open/save dialog boxes and in 3rd party file managers was to hack shell32.dll or user.exe with apps such as exescope ...