i can boot bt5 iso from grub2, but no in grub1.....
I don't think grub1 supports booting from ISO, but I could be wrong.
Burn the iso to a disk is the easiest way.
Of course, if you really wanted to have some fun, go to Wal-Mart late at night and ask the greeter if they could help you find trashbags, roll of carpet, rope, quicklime, clorox and a shovel. See if they give you any strange looks. --Streaker69