WMC Is Reporting Service Unavailable on ALL Channels

[rpammons]

My problem is similar to the single channel problem, except it is ALL channels. I have tried what you suggested and worked for that person, but it didn't' work for me. My problem surfaced about the time his did; I wonder whether a Windows update I did between the last success and the first failure may have caused a problem, or switching from Norton to McAfee for my virus protection.

When I go to edit source, it shows two entries for each channel, one associated with each tuner. There are no extra copies.

The long version:
I have been recording using WMC just fine for a couple of months. However it started not recording a few days ago- just leaving a 512KB file with the name, but no video, and apparently does not think it has an input signal.
When I try to watch live TV on WMC to see if WMC is getting the signal, I get the error message "Service Is Not Available. There is currently no TV signal detected for this channel. Channel may be temporarily off the air. Try again later." When a show was supposed to start, the same error message popped up that there was no signal, so it would not be recorded (paraphrasing - the error message was only up for a few seconds).
The TV station(s) are on the air. I am using SiliconDust Homerun ATSC Digital TV tuners (two) and they test out fine. I can watch live TV on them. WMC reports that their signal strength is good. to excellent on all channels.
I ran "Settings/TV/TV Signal/setup TV Signal" on WMC again. It examined TV signals, found the tuners. I configured WMC with the tuners and got a very fast response that WMC was configured with the tuners.
No change - no live TV. I then went into setup again and checked Digital TV antenna signal strength. Good on all channels.
Still no Live TV and the same error message.
I ran "scan for more channels, but it ended with "no channels found" (not "No additional channels found").
I don't know what to do next and would appreciate any help.
Posts on the tuners website didn't help. I tried several of their suggestions (remove WMC eHome files since they might be corrupted), but nothing changed. Spent about two hours with a Microsoft person on my machine. He did a lot of things but nothing has changed. Haven't gone for another attempt yet.
I thought it might be the McAfee load over the weekend, but I uninstalled and re installed. WMC exhibited the same symptoms between uninstall and re-install and after re-install - nothing changed, so that is probably not it.

[curtis]

I'd recommend using system restore to go back to a time when it worked as even uninstalling McAfee doesn't actually remove all of its bits and won't fix any system files it might have affected (if it was the issue).

[TeddyR]

Just uninstalling is not enough for some AV products. You may have to use the specialized removal tool. For Mcafee try the ones from http://service.mcafee.com/FAQDocument.aspx?id=TS101331 .

Once uninstalled, reboot and rerun the SD software to reinstall / repair the software install so that the "blocked" drivers/dlls/etc get reinstalled and the firewall rules to allow the communication get reset.