If you want to install linux on your Win2k hard drive you have a couple of options. First and foremost, you need to partition your hard drive. Partitioning is basically dividing your one physical drive into many sections. The only problem with partitooning a hard disk where a file system already exists is that it tends to destroy the file system. The best idea is to resize the current file system, to make space to install linux. There are many programs which can do this. If you would rather buy a program, get Partition magic. If you do not have the cash or don't want to pay it, www.sourceforge.net
has many programs that I myself have used with success.
After you have freed up some space, your Linux install may take you through it. Slackware and gentoo however will not partition for you. I don't suggest them as your first distribution. Redhat and Mandrake are good places to start and will help you start to finish.
If you have anymore questions please ask them, and welcome to Linux.