Hello After Knoppix 32 bits, I tried the live-CD Kubuntu 5.10 AMD64. All right during the whole boot up to KDE session (3.4.3). This is based on a kernel 2.6.12. After several minutes of use, I lost the mouse !!!!! I plugged it in an other USB port => mouse available again. But in the same USB port, not possible to get a working mouse. It appears with such a test that there is a serious problem with kernel >=2.6.11 64 bits for a given hardware based on chipset nVidia nForce3 150. A user of Compaq Presario 3140 laptop (almost equivalent to my laptop) has a similar problem but with SuSE 10.0 64 bits. This is a kernel 2.6.13 ... For gurus and linux experts, what's new in kernels > 2.6.8 and leading to such a problem at USB level ? Regards Pascal