This problem drove me crazy for 2 weeks on and off. I have finally found out what the problem is and I registered just to share my conclusion to help others because this is a very misleading error to a lot of us.
I have 2 laptops and I tried to install BackTrack, BackBox, Ubuntu, etc.. all failed on one laptop and I couldn't understand why, I was installing from a live USB and it was still complaining about the CD/DVD error!! what the hell, it does not make any sense.
I opened up my laptop, I completely removed the CD/DVD and tried again and it still failed.
I opened up my laptop hoping my final resolution was to just remove a 2GB ram but to my luck, the laptop had just one 4GB RAM stick, so that trick would not work.
I came to the wrong conclusion that others came to as well and that is perhaps the linux OS is just not compatible with all hardware out there and in my mind I started to blame developers even though I am one.
Why this problem is a misleading one? Because:
You can go into your bios and detect that you have the correct size of ram (4GB) and also boot windows 7/8 and use it just fine, no problems at all, so why should Linux complain !, also in my case this was a brand new laptop as well.!!
There is a large number of us users that are actually experiencing this problem, so this could lead to the understanding that it is actually the OS and not our hardware. However, until you restart your machine and go into “Diagnostics” you won’t know that there is actually a problem with your ram, Its much quicker than using memtest to detect if there is indeed an issue.
This leads me to believe that linux is actually so good that it does a proper test of the CRC of your ram as it tries to install itself and will fail if there is something wrong with the ram, a bit harsh though.
Having said that, linux developers still need to change the error message to help the users understand clearly that there is a ram issue as oppose to a missleading "CD / DVD error" but also there should still be a way to bypass the error and continue the installation of the OS because we know that windows can operate just fine on the faulty ram.
I replaced the faulty RAM and it worked just fine. I really hope this helps people to cut to the chase.
When people are suggesting to remove 1 ram and got it to work, they most definatly removed the faulty ram, its not because it was a trick to remove one and keep the other to fool the OS.