Stop mouse from waking pc from standby mode.

Hi,i have windows xp PROFESSIONAL.
I can`t find a setting anywhere that will stop the PS2 mouse from waking my pc from standby mode.I`ve been into the control panel,checked all settings under the mouse heading as well as accessibility options and not a setting to be found anywhere.
What`s really strange is that on our second computer which runs windows xp HOME,there IS a setting to stop the mouse from waking the pc from standby mode under one of the headings listed above----why would there be a setting for it on the HOME edition and not a setting for it on the PROFESSIONAL edition?
Perhaps there is a bios or registry setting that might fix it,i don`t know.
Any help will be appreciated-----the slightest mouse movement wakes the pc and we want to put a stop to it.

 

It's there I think...control panel/mouse/hardware tab/properties/power management tab...see the checkbox. Good luck.

 

...actually its control panel/printers and other hardware/...then mouse.