So there it is. Probably safe but will not result in anything usable.
Using XP home, sp3, auto updates.
My wired mouse came with an adaptor to convert round to rectangular to plug into my computer USB port.
I now have a wireless laser mouse 5000, and the receiver has a rectangular plug for the USB port.
Can I safely use that adaptor to plug the receivers USB plug into the ROUND port on the back of my computer?