[gambatte]

That's strange. I can go back and forth between the 6700 and XP Home/AS4.5 and Vista Business/WMDC 6.1. I would try deleting the partnerships for the XP synch first, rebooting PC/soft reset 6700, and then remaking. Hopefully, it won't break the Vista partnership. Something that some ppl report is that WMDC causes the 6700 device name to change. You might check that to see if it has done that. That will effectively break the AS 4.5 partnership. It is some weird format so you should know. AS 4.5 can be downloaded from the Microsoft website but I wouldn't reinstall just yet.

Edit: Oh, and when you do remake the partnership uncheck the advanced networking (communication?) option. I can't remember what it's called right now either. You'll see it.