Suddenly no channels found using Volar HD Pro

Hi, I have Aver Volar HD Pro USB tuner and I have been using it with WMC on W7 x64 for some time without any problem. But suddenly, low signal message appeared and when I tried to rescan channels, no channels were found. Sometimes (not very often) it actually finds 2 or 4 channels, but it still can't play them.

One might suggest, that I really have weak signal, but when I connect it to different computer, it works really well on the same home antenne. I have tried newest drivers, clearing WMC configuration, different USB ports,... but without any success

I really can't see where the problem might be. Does anyone do better?

I had the same thing happen a few days ago, using 2 different tuners, a Compro E800F and a Tiny Twin.
The tuners worked with their own software (which is crap) but Windows couldn't find any channels. After pulling what's left of my hair out, I decided on a different aproach.
I found a restore point for 11 Jan and ran the restore. Everything working again.