Summary: If I had to speculate about the Windows XP thing, maybe that was with the PS/2 adapter on it? PS/2 interfaces are not plug and play. Pull it off and use the USB interface. I didn't try the PS/2 adapter myself. Tested on Windows 7 64-bit and Windows 8.1 64-bit, no problems.
Pros: Small. Colorful. Works.
Cons: Couldn't persuade my three year old to use anything but her thumb on the mouse. Beyond that - uh - not wireless?
Summary: This is a great mouse for children. Very comfortable and easy to use. Definitely works with XP...not sure what the other reviewer is talking about. I always figure, if you have a problem contact the manufacturer. Chester Creek is always very responsive.
Pros: Small, for my child's small hands easy to use definitely plug and play cute colored
Summary: Bought this for my two year old. I set up a computer for him and the standard mouse was just to big. This one is perfect for him. He was able to use it right away. I did find it difficult for me to use if I'm trying to help, but I have big hands. I just installed a wireless mouse as well and I can turn it on if I need to help him. One of the reviewers said they were having problems with MS Vista.