Mouse driver is blocking standby

Logitech MX518 mouse
WinXP Pro SP3

I uninstalled Logitech SetPoint 4.24 and installed SetPoint 4.60. Since
then, I get an error whenever I try entering Standby mode. The error
says that the Logitech mouse is preventing the system from entering
Standby.

When I look at the mouse in Device Manager, the "Allow the computer to
turn off this device to save power" option is greyed out.

I uninstalled and reinstalled SetPoint but the problem remains. I have
not tried reverting to SetPoint 4.24, since the whole reason I updated
was to try fixing a whole separate issue I'm having. Other ideas are
welcome.