Booting into DOS is a useful thing. There are several DOS utility and diagnostic programs that I use, like memtest86, etc.
Some programs, like memtest86, are available as CD images that you can burn onto a DVD or CD. I often use CDspeed for this, but Nero can do it if you know what buttons to push.
When I don't have a CD image available, I use a more complicated procedure. I don't know if your are interested, but I'll tell you how I do it.
First I start up a virtual floppy drive. It can be a little confusing to use virtual floppies but I have used them many times. I can tell you this, they are much faster than real floppies and they never have bad sectors either.
You can download the virtual floppy drive here:
Maybe there is a little help here:
Then XP will format it and make it a DOS bootable floppy. I think you need to check a box at the bottom of XP's format window to do that. You can have 1.44 meg and 2.88 meg virtual floppies, but XP will only make 1.44 meg floppies DOS bootable.
Then copy the DOS files to it. Then Nero can make a bootable CD or DVD that emulates a bootable floppy. You might need Nero Burning ROM for this, I don't know if Nero Express can do it. But there are probably other utility programs that can do it also. Whenever I make a bootable CD/DVD from a "bootable" virtual floppy, Nero will pop up a quick message about a non-fatal error and keep on going. The resulting DVD or CD works though, and that's what matters.
Note that a good virtual device, and this one is pretty good, will fool XP (and Nero) into believing it's real.