Help milestone USB not connecting to computer

[fdisk]

hello
I'm facing the following symptoms:
1) when I connect my milestone to my windows XP, the milestone gets charged, but the PC doesn't even do the "USB plugged" sound
2) it works on another computer
3) it used to work on this computer
4) milestone doesn't show the "USB" icon in notification bar
5) I already tried with debug mode on/off

anything else I can try?

thanks