From our stand point the only thing we can think that it may be is our DNS Servers. Because of our recent move to the new office our secondary DNS server has moved too. And unfortunately we forgot to update the new IP address with Network Solutions. So because of this DNS lookups may not have been working properly which could have possibly caused some of these issues.
We have updated our our DNS records to point the secondary DNS servers to the correct location. However, this can take time to propogate the internet depending on how frequently your DNS servers picks up updates.
One possible thing to try is run the following command from a command/dos prompt:
ipconfig /flushdns
This may or maynot help but may be worth the try.