Answer by ish for Dual Boot Installing Ubuntu 12.04 with Windows 7 (64) on a non UEFI system

You are making a mistake somewhere. The LiveCD does NOT use grub as a bootloader, it uses Syslinux.

1. Boot from the Desktop Live CD and press the Down-Arrow when you see the below:

2. Press Enter and select English:

3. Press F6, go down to nomodeset, and press Enter. You will see an X next to it. Then press Esc, and "Try Ubuntu"

4. If the above doesn't work, repeat steps 1-2, but press F6 and then Esc to see the command-line. There, replace quiet splash with nomodeset and press Enter.