You can save files (Banking info,smaller programs,etc.) onto a cd or a flash drive as mentioned above. I thought the OP was asking if he could make a copy of someone else's Vista and put on his computer. Which can be done, it is called cloning an operating system - but it isn't a beginner's task, which is why I referred to pc website. So he could read what was involved/at risk and make decision on his own... I clone my OS at first boot, so if there's a problem I just pop that in, and i'm right back to where I was!!!
***I back-up to flashdrive everynight, btw...***
OP: Search and there are Key generators still out there for XP!!! Google's your friend!!