Caroline has a charming new hobby. It reminds me of an experience I had ten to twelve years ago when I was living in Queensland. I had gone to visit this guy that ran a computer shop out of his backyard to buy some software and he showed me a CD that he had which contained the assembly code for a few thousand computer virii.
At the time I was tempted to buy a copy of the CD, but I suspect that if I did it would have led me down the path of growing that collection. At the time most computer virii were DOS-based and injected themselves in the boot sector.
In many ways I think this was more sinister than the variants we have today (although the ones today have much more nusiance value) because it was more common that they would cross infect machines by automatically copying themselves to removable media. While current Windows-based virii do sometimes do this their preferred method of distribution is e-mail so if you practice safe computing you are unlikely to get infected.