I would like a new mouse but sadly, my PC will not let me!
My current mouse is plugged into the mouse PS2 port at the rear of my desktop via a green adapter as it has a USB plug. If I shut down, plug another mouse with a USB plug into the same adapter, and reboot, nothing happens - I cannot move the cursor and there is no indication new hardware has been added.
If I plug the new mouse's USB plug into a USB socket and reboot, the system tray and Windows new hardware/driver wizard opens but I cannot move the cursor to start it!
With the old mouse fitted I have checked what I consider to be the relevant drivers in Device Manager but all are reported as the latest.
Please help, this is driving me crazy.
So much for Plug & Play!

Fixed! Plug in new mouse and use old one to enable!

If you use the PS/2 adapter then your USB mouse becomes PS/2. PS/2 requires a restart to be detected. Same with a keyboard.

Turn the PC on then unplug the keyboard and plug it back in...you won't get a response until you restart.

If you have already restarted with the new mouse connected and it hasn't worked then try going into Device Manager and then uninstalling the mouse and clicking Actions > Scan For Hardware Changes.

Looks like you may have to do some fiddling about with the keyboard. You can actually use a PC without a mouse.

The keys you need are:

Tab (above Capslock) - switches between different options such as Next, Back, etc
Menu (between Alt Gr and Right Ctrl - does the same as right clicking the mouse
Arrow Keys
Enter/Return

Use those to access Device Manager / Use the Add Hardware Wizard.

Although if you turn the PC off and connect the USB mouse with the PS/2 adapter then I see no reason why it wouldn't work straight away when you turn it on.

Are there any bent pins in the PS/2 connector?