Are these USB or cordless?
I have Logitech Cordless k/b and mouse. Kit has USB-powered receiver, mouse
and k/b battery powered. As I read the documentation, battery power cuts out
after 2 minutes inactivity.
However - when the pc is OFF (via "on/off switch" on case front) the
receiver lights remain "on".
(There is also an on/off switch on the PSU rear of the tower, -
inaccessible, therefore always on).
By "mouse light", do you mean the optical light on the bottom, or does MS
mouse have an indicator light on top?
Point being - if USB, and your pc mains PSU is similar to mine, then USB
ports are clearly still receiving power even though the pc system is shut
down and disk drives off. Same would apply to USB mouse.
If battery (self-powered) your mouse optical light will remain lit (because
there isn't an "off" switch on the mouse) for a while, until the pre-set "no
activity" detector cuts it out.
One last important hint for cordless mice, from Logitech support - cordless
mice need plain light coloured, preferably white, mouse-mats. Dark
colours/heavy patterns confuse the sensor and can prevent the auto-cutout
working, thus shortening battery life. Changing mouse-mat almost doubled my
mouse battery life.
Hope there's something useful here for you! Sincerely, Len.