I have a similar problem. I'm on Charter in Missouri and they have a strict policy against running websites.
Well, I ran my IIS server and they shut my modem down. I have no idea how to get it back up. I know they sent some kind of signal to my modem (or somehow blocked the MAC address) because I hooked up another cable modem here and it worked. I have a Motorola Surfboard and ever since they shut me down for running my website, the powerlight just flashes on and off while all of the other lights stay constant. I've tried to restart the modem numerous times. No luck.
Any suggestions?
Thanks
Sam
**edit** I forgot to mention that this happened before and somehow it fixed itself overnight. This time it's been down for a long time.