>Is there a way to make work a mouse on com2.I have a Cash Register that only work on COM1, so I'd like to make mouse work on com2.

There should be no problem with this - WinNT and Win9x will sense this automatically; if you use a real-mode driver under DOS or Win9x, you might have to change a port or interrupt parameter on the line that loads the real-mode driver in your CONFIG.SYS or AUTOEXEC.BAT at most.