If the cable modem lights are doing that, consider reducing the number of devices on your cable network (yes, it is a network.)

The cable company usually sets you up and measures signal power at the cable modem but time and time again I see folk add more TVs or other things but not have the cable co re-test this. And no, I don't write about this as a DIY method.

One last idea? Be sure the cable modem is cool. That is, don't stack a router or phonebook on top of it.
Bob