okkie; Now-a-days things have gotten more complex with booting issues. Many times it is a UEFI or Intel Smart Response Technology - dual boot issue.
Was Windows installed/still installed ?
Did you verify the md5sum of the .iso file ?
The hard disks ever part of a "raid array" ?
How is the hard disk partitioned // MBR or GPT ? MBR can only have 4 primary partitions per disk.
Can you boot the install medium to the boot screen and choose the option to verify the installed medium's integrity ?
where there is a will there is a way