From security system (Norton360) logs, here's  just a sample:

4/29/2010 7:24 PM,Info,"IP address has disappeared from adapter Microsoft 6to4 Adapter #4 and is no longer being protected (IP address: 2002:182f:c54a::182f:c54a)."

4/29/2010 7:24 PM,Info,"IP address has disappeared from adapter Realtek RTL8102E Family PCI-E Fast Ethernet NIC (NDIS 6.0) and is no longer being protected."

4/29/2010 7:24 PM,Info,"IP address has disappeared from adapter Realtek RTL8102E Family PCI-E Fast Ethernet NIC (NDIS 6.0) and is no longer being protected (IP address: fe80::f151:d01e:3b0e:7723%10)."

4/29/2010 3:47 PM,Info,"IP address has disappeared from adapter Microsoft 6to4 Adapter #4 and is no longer being protected (IP address: 2002:182f:c54a::182f:c54a)."

4/29/2010 3:47 PM,Info,"IP address has disappeared from adapter Realtek RTL8102E Family PCI-E Fast Ethernet NIC (NDIS 6.0) and is no longer being protected."

4/29/2010 3:47 PM,Info,"IP address has disappeared from adapter Realtek RTL8102E Family PCI-E Fast Ethernet NIC (NDIS 6.0) and is no longer being protected (IP address: fe80::f151:d01e:3b0e:7723%10)."

4/29/2010 1:54 PM,Info,"IP address has disappeared from adapter Microsoft 6to4 Adapter #4 and is no longer being protected (IP address: 2002:182f:c54a::182f:c54a)."

4/29/2010 1:54 PM,Info,"IP address has disappeared from adapter Realtek RTL8102E Family PCI-E Fast Ethernet NIC (NDIS 6.0) and is no longer being protected."

4/29/2010 1:54 PM,Info,"IP address has disappeared from adapter Realtek RTL8102E Family PCI-E Fast Ethernet NIC (NDIS 6.0) and is no longer being protected (IP address: fe80::f151:d01e:3b0e:7723%10)."

4/29/2010 4:54 AM,Info,"IP address has disappeared from adapter Microsoft 6to4 Adapter #3 and is no longer being protected (IP address: 2002:182f:c54a::182f:c54a)."

4/29/2010 4:54 AM,Info,"IP address has disappeared from adapter Realtek RTL8102E Family PCI-E Fast Ethernet NIC (NDIS 6.0) and is no longer being protected (IP address: fe80::f151:d01e:3b0e:7723%10)."

4/29/2010 4:54 AM,Info,"IP address has disappeared from adapter Realtek RTL8102E Family PCI-E Fast Ethernet NIC (NDIS 6.0) and is no longer being protected."

4/29/2010 4:43 AM,Info,IP address has disappeared from adapter 6TO4 Adapter and is no longer being protected (IP address: 2002:182f:c54a::182f:c54a).

I've gotten 70 of these in the past 24 hours. 6TO4 chronically dead...the old fixes not working ANYMORE. Any info would be greatly APPRECIATED. Thanks!
I'd try a brand NEW nework card for 15 Bucks...Thanks.