after many many..(x10) tries and tests, i can say i have a direct conflict between my Microbook and my USB mouse, 3 things first :
1° when i start windows 7 with both of them plugged in > win7 recognizes the mouse, but when i open the "CueMix FX" of the Microbook i have the following screen :

and each time i have this, i know Microbook doesnt work
2° when i first plug the mouse and then the Microbook > mouse : Ok ; but the same screen for the MB,
then unplug mouse + MB and reconnect MB > MB works ; then reconnect the Mouse > the mouse doesnt work
3° same as "2°" inverting mouse & MB
yup sorry it's a bit long but i try to be as detailled as possible
so, i'm quite sure it's not a bus powered problem because i tried :
- MicroBook + Mouse > doesn't work
- MicroBook + Novation Keyboard + Tascam interface + Hard Disk (all Bus powered) > and all work !!!
i also tried of course to switch between many ports, to try with another USB mouse > nothing works
i really don't know what to do and i don't want to have to work on my compositions with the touchpad !
please find me something !

my configuration :
- Laptop : ASUS X52J series / i5@2,27 / 4Go RAM
- OS : Windows 7
- Motu MicroBook Firmware 1.07
- Driver v4.0.44925 (i also tried with the one on the CD)