Also another alternative to Dual Booting is the use of virtual machines now. Programs like vmware
can launch another system in windowed form and just borrows resources from your host OS.
I personally have never dual booted a system but have used a VM when wanting to mess with things (mainly LINUX) and was afraid of messing up my whole system.
The only downside really is that any information saved in the VM cannot be transferred over directly to your host OS, you would have to use some sort of external storage device (External HDD or flashdrive) to transfer it.