Before you do anything to your computer, I suggest you try knoppix.
The disk has everything you need to try out linux.
If you are serious about linux then....
You will first need to repartition your hard drive.
Prep for repartitioning:
First defrag vista. That will make sure that will put most of the files together. I have xp/slackware so I am not sure about vista.
In xp>start>programs>accessories>system tools>defrag disk.
I found the best partitioning software is QTparted.
I like the gui. http://qtparted.sourceforge.net/
Download and burn on disk qtparted
You will need to make the vista (NTFS) partition smaller to make room for the Fedora (Reiser) partition.
Why do you want to use linux? That will depend on how much room you give for fedora. If you are planning on sticking with linux, I suggest to cut the vista partition in half.
You will need to setup a swap disk partition of about 1g.
The rest you can partition for reiser.
Once you get your partitions setup, reboot your computer in vista.
If it works and you have no problems you are doing great!
You might have to reinstall or repair vista. On my kids computer, I had to reinstall windows. Luckily it was a new computer without alot of programs.
Once you have the partitions setup and vista working, and a linux-swap disk. You are ready to install fedora.
Since I don't have fedora, I am not sure what is the process. Ive installed Debian and Slackware.
Just carefully read the install instructions.
Hope this helps.