I recommend to make a seperate NTFS (or FAT) partition on your harddisk for Mint4Win to avoid fragmenting of the Mint system.
Windows 7 versions that can open ISO files:
Open ('mount') the ISO and run mint4win.exe.
Vista and before:
Burn the Linux Mint KDE ISO file to a DVD, or place it on a USB pendrive.
To place it on a USB stick: download Universal USB Installer from www.pendrivelinux.com
As it does not support Mint 10 KDE by default, rename the file: replace kde with gnome. KDE still works, but Pendrivelinux thinks that you have gnome and runs fine.
After you have put it on DVD or USB, put the disc or stick into the computer that you want to use. Mint4Win will open automatically, if it does not, browse to the file mint4win.exe that has appeared on the disc/stick and open it.