You may have heard of ubuntu/linux/some other distro and want to try it out, or want both, or don't have a windows CD and don't want to have to pay for it again if you screw something up. There is an easy solution. Wubi. Wubi dual boots ubuntu and the copy of windows you already have on the same partition by installing ubuntu as a program in windows. This method's User Interface is the same as any other dualboot, just if you start ubuntu you have to press enter twice instead of once.
1. Download Wubi, This one worked for Ubuntu 10.4, and is supposed to for ubuntu 10.10 http://download.cnet.com/Wubi/3000-2094_4-10701841.html
2. run the exe file(it can download a ubuntu ISO but it takes forever, download one straight from the ubuntu website)
3. it may take awhile, if it errors, do it again
4. reboot, choose ubuntu, then the top option, Ubuntu Generic
5. it will do the default ubuntu install, don't wet your pants
6. follow the setup steps, reboot after, choose windows or choose ubuntu--> ubuntu generic to start windows or ubuntu, irrespectively.
1. open windows, if your computer does not, go to the boot menu
2. (only for if you go to the boot menu)unplug all wires except power choose your hard disk/SSD(if you don't know what that is, you don't have it)
3. choose windows
4. sign in to an admin account
5. uninstall the program "ubuntu"
6. restart, if wubi, grub loader, or no menu opens at start up, you didn't follow instructions(I did this twice on each of the 5 PCs I own and they all worked)