Thanks bair ohio.
The problem is it had working until I touch something o I don't know what!!!!
I try unistalling this stuff, and reinstalling drivers, WinXP, etc.
And the same problem. When I restart, in the control panel not appears the MM. Only when I unplug and plug it, the PC "see" the MM.
Also, I will like to keep the sound card (it's integrated) for another things.
Thanks again, and sorry for my english
(I live in Spain)