nWindows XP
includes a remarkable new technology called
Windows Side by Side (WinSxS) isolation support
nBy default,
Windows checks DLLs and other common code
components before installing them on a computer
nIf it finds potential conflicts, it automatically makes
the Registry modifications
necessary to point to alternate versions
of DLLs and other shared objects in a special directory named %systemroot%\WINDOWS\WinSxS