It should save a copy of your old BIOS wherever you flashed it from: A: drive, or a subdirectory on the C: drive. That way you can restore the old BIOS if the new one doesn't work out. Of course it won't help if you totally hose the BIOS and can't boot up at all. If that happens and you have an old ISA video card, you can boot up from the boot-block section of the BIOS and re-flash.
1.Old Antec Case, Asus PC-DL, 2 x 1.6 LV D1 Xeons @ 3 GHz, 2GB Corsair PC3200 @ 200 MHz, Chaintech 6800 128MB AGP
2. Old Crap Beige Case, Gigabyte GA-H55M-S2H, Core i3 530, 4GB CL8 OCZ DDR3-1600, eVGA GTX465
3. Asus Pundit mATX Case, MSI AMD Zacate E350/dual core E350IS-E45 mini-ITX, 4GB CL9 Crucial Ballistix DDR3-1333, LG Blu Ray/HD DVD & DVD Burner