The best thing to do is this. Download YUMI, or some other USB multi-boot utility. The thing I like about YUMI is that it will automatically put whatever bootable OS's you want on a USB stick, has links to a huge number of distros, will install many of them on the stick for you automatically, and YUMI itself doesn't require an installer. You can just run YUMI whenever you want to add another OS to your USB. With most USB's these days you can have quite a few Linux, FreeDOS and other standalone distros on one stick. YUMI will create a menu that allows you to soft-boot the one you one after the hard-boot.
You can get that here: http://www.pendrivelinux.com/yumi-multiboot-usb-creator.
I would recommend at the very least that you put
- FreeDOS
- GParted (Partition Tools)
- Memtest86+ (Memory Testing Tool)
- System Rescue CD
on the USB. All of them are dead useful; YUMI has entries for all of these, just pick 'em on the distro menu and YUMI will do the heavy listing of putting them on the stick.
You can cleanup the partition after booting the stick with gpartd. If your USB is 16GB or greater, you can also add your Windows installation CD to the USB stick, and do your Windows installation from it as well. It will be much faster than installing from the CD.
Good Luck.