Comcast XFINITY TV → Is comcast now encrypting network channels??

I have been using Hauppauge's HVR-1250 tv card on my Dell Desktop with W7 for 3 years now, and just recently found it no longer works with Windows Media Center on network TV channels. It receives only local PBS channels.
I am using Comcast in Annapolis MD.
Does anyone know if Comcast recently encrypted all their previously available basic cable programming. I suspect they may have to collect a digital box rental fee.
Thanks for your help

Some other subscribers in your "Beltway" region have recently reported a similar thing »Re: Is Comcast dropping local HD channels in "open QAM"

If a "rescan" doesn't recover those channels, then it looks like Comcast may have encrypted them now, though you should have received a notice of that at least 30 days in advance.

Also see: »customer.comcast.com/hel ··· ryption/

Most areas comcast encrypted the locals a local only sub gets free DTAs. Up to three free.

I live in Montgomery County, MD and Comcast has not encrypted the local HD channels along with several other HD channels (TNT HD, Universal HD) and Newschannel 8 HD) yet. They need to give a thirty day notice which would be shown on your bill and at that time they should make available HD-DTAs.

Thanks for the link -- OP is about 50 miles away from me on the far side of the Beltway. As far as I can tell from anecotal evidence, Comcast Virginia and Comcast Maryland rarely coordinate actions. The nearly simultaneous change may be nothing more than a coincidence.

We've also had service less than 30 days so we may have missed the notice on the encryption changeover.