Thanks dencorso, I think I'm fine with what I have, then. I have a 5.2.3790.3959 usbhub.sys and in the properties it mentions SP2.
I have a newer one, 5.2.3790.4555 , from some later hotfix update, props: 5.2.3790.4555 (srv03_sp2_qfe.090718-1230)
I got second time restart when launching BlazeDTV app for DVB so it's not just a coincidence. I googled hard and found a newer FlyDVB hybrid PCI tuner driver (2 years after current) that is unified for WinXP-Win8.1 so I could hope that it will help.