Have you checked if the kernel sees the mouse? If not, it's definitely a hardware problem. But if the mouse is just inactive in X, that could be an issue with the evdev driver. Open a terminal and type
then scroll down to find the mouse code (if present). For example, mine reads:
Code:
[ 10.595726] usbhid: USB HID core driver
[ 10.612918] input: PixArt Lenovo Optical USB Mouse as /devices/pci0000:00/0000:00:14.0/usb1/1-3/1-3.4/1-3.4:1.0/0003:17EF:6019.0001/input/input10
[ 10.613633] hid-generic 0003:17EF:6019.0001: input,hidraw0: USB HID v1.11 Mouse [PixArt Lenovo Optical USB Mouse] on usb-0000:00:14.0-3.4/input0