For you I'd try a different Linux Distrobution. One that's easier to install. Fedora has a 64 Bit version and installs easily and beautifully. Make 1 partition, about half the disk, and leave the rest blank, and install windows first. Linux will make it's own partitions in the remaining space. You'll want both windows and linux because there are almost no good linux games but you'll not get 64 bit support from a standard windows install, so you'll want linux for that. Games that run on linux will say so on the box or have the words "for linux" on a web site if you download it. Windows and Linux software is pretty easy to tell apart. if it's in a .tar.gz file then it's probably linux. if it's .zip or .exe then it's windows.
For future reference. If you get fed up with linux and want to delete the partition and just have windows, but after you delete it GRUB wont go away, get a regular windows 98 boot disk, boot from it and then type fdisk /mbr