Hey, this was taken from Logitech's recent update readme notes:
3.1 Standby on Windows XP doesn't work for PS/2
If using the sleep key with a MicrosoftXP OS, the first function
will take you to the log-off screen. If you select the sleep key
again, no function will be performed.
Is that what you are talking about, the sleep button on the keyboard? It sounds like this recent update Logitech iTouch 2.15, filename: it215enu.exe for some reason messed up your sleep button.
I love it when a company tells you that their product does not work right with your system and offers no work around -- don't you?