CM700

> [...] the Ethernet LED has been flashing green non-stop [...]

   According to the CM700 User Manual:

Ethernet
          o Green.  A powered-on device is connected to the Ethernet
            port at 1000 Mbps.
[...]
          o Blinking green or amber.  The Ethernet port is processing
            traffic.

   One interpretation of a flashing green Ethernet LED would be that the
device which is connected to that port (perhaps a router?) is sending or
receiving data through the CM700.

> [...] the network has become extremely slow and unstable in my house.
> What is causing this?

   All I know about your network is that you have a CM700, which, I'd
guess, is not the source of the problem.

   If some device on your LAN has gone berserk or has been hijacked,
then that could account for a flood of traffic, which might be
interfering with the traffic you care about.  What are all your other
LED indicators indicating?  Assuming that you have a router of some kind
connected to this CM700 port, can you get any information from it about
what it's doing?

   Last ditch: Start shutting down or disconnecting your devices until
the problem traffic subsides.