Recently, I've ran into a problem regarding the Hamachi network driver which just wouldn't install. I thought it was a hamachi specific problem but turns out I can't install any other driver either, I've tried updating my video drivers, sound card drivers and network adapter drivers, all of which fails, but the older drivers were removed. I had to boot into safe mode in order to be able to install these drivers.
Maybe it's some kind of virus? I don't have the option to format this PC, because my windows 7 instalation disc is miles away and this internet connection is too slow.