Windows 7: WMC 7 - OTA channel KABC-7 suddenly gone - works on regular TV

I have been recording over-the-air TV programs on WMC 7 without problems. All of a sudden last night, around 10 PM, I lost the signal for KABC-7, our local ABC affiliate in Los Angeles. All of the other channels seem to come in fine. I re-did the TV signal setup and re-scanned for channels, but it is the same problem. Almost all of the other channels come in, except for KABC-7 - which is a problem because I want to record Game 5 of the NBA finals tomorrow! I usually record and watch these games after we put our kid to sleep. The station comes in perfectly fine if I plug the antenna directly into my TV. My TV card is a Hauppauge 1229 WinTV-HVR-2250. Has anyone else run into a problem like this where a station comes in perfectly for months, even years, and then all of a sudden is gone?