Hum... i tought of that, of being a problem of the tvcard... unfortunately i don't have any other to test this, but that's strange because besides that it captures perfectly well all the time... Oh by the way i almost forgot to say, sometimes, rarely and seemingly at random, in some of those 1 hour freezes, it does NOT drop any frames at all. I suppose that the freezes sometimes are stronger than in others. But it's not normal that in windows xp i never had these problems at all.
Oh by the way there's something very very weird about the midnight freeze (which is always stronger since i get about 15-20 dropped frames and the freeze lasts one second) : it does NOT happen if i change the clock manually, even if i change it in the bios before starting windows ! This is amazing, i don't know how is this possible but during the day i tried to change the clock to 11:55pm and then i waiting for the midnight... and NOTHING happened! Then i did the same again, but this time i changed the clock in the bios itself, and still couldn't reproduce the freeze. Then i just quit this, and later when the clock naturally reached 00:00 there is was the freeze! This is amazing... it's a curse i say
And yet another very strange thing : it also drops 20-23 frames EXACTLY when the captured video time reaches 01:23:33, always ! This also never happened in windows xp.