Synergy lets you easily share a single mouse and keyboard between
multiple computers with different
operating systems,each with its own
display,without special hardware.
It’s intended for users with multiple
computers on their desk since each
system uses its own monitor(s).
Redirecting the mouse and keyboard is
as simple as moving the mouse off the
edge of your screen. Synergy also
merges the clipboards of all the
systems into one,allowing
cut-and-paste between systems.
Furthermore,it synchronizes screen
savers so they all start and stop
together and,if screen locking is
enabled,only one screen requires a
password to unlock them all.

P. S.

参见how to fix Synergy problems on Vista。