Will it melt? PC help please

[LumpyGravy]

My laptop's gone into meltdown today. Something was installed yesterday by my sister, a bit of software for a no name digital camera... I can't see how that has done anything but it's the only thing I can think of, since then I've just been getting boot failures (Vista btw). I run regular virus/spyware etc checks.

I've cursed myself as I haven't set up a system restore point, and none of the Vista auto repair business or diagnostic tools from the "techguys" boot failure screen has turned anything up. So, I cut my losses and decided to completely reinstall Vista and go for a full destructive recovery.

To get to the point, this has been taking a worryingly long time now- it's been on the "in progress" screen for a good few hours now. Apparently it should take between 25 and 40 minutes. There was an error message near the beginning but it kept on going and I thought nothing more of it...

If I was to cut the power would I be able to restart the vista reinstall? Obviously I don't want to bjork it any further... If there's been some error that is stopping the reinstall from taking place, is it safe to start again?

Thanks very much for any help, I'm very n00bish with computers.