Are you doing an in-place Upgrade or clean install?
Are you continuiing to "press any key to boot from DVD" during restart? If so, don't do it again after the very first time you boot install DVD.
Please fill out your system specs in lower left corner.
Are you using the latest BIOS versions update? Check against the latest update given on your computer or mobo model's Support Downloads webpage on manufacturer's website.
In BIOS, what is SATA controller set to? Try AHCI first, then IDE if that fails.