Hi there,
I was planning on installing windows 8 on a second partition, and leave windows 7 on my current partition. However, will windows 8 delete the other partitions and their files during installation? Or would the other partitions be safe?
Other partitions will be safe. The Win8 installation partition should write an entry to the MBR and when you turn on your PC you should be given the option to choose which OS you want to boot. Make a backup image with Clonezilla beforehand just to be safe.