So like many people I hit Google at this point. After much reading I found that my system like many others must not support primary disks of above 2TB, even though the operating system can, the hardware could not. I updated my Dell BIOS from A02 to A16 which requires you to download a file from Dell and then just run it in Windows and wait 10mins and the system will then reboot with the updated BIOS version. But this did not fix the problem. There is a very good article I found here ( http://www.pcworld.com/article/235088/everything_you_need_to_know_about_3TB_hard_drives.html ) that explains the 2TB and above issue in detail, so no need for me to type up pages of info ! Plus have a read of this Microsoft article that answers many questions also – http://msdn.microsoft.com/en-us/library/windows/hardware/gg463525.aspx
Apparently I read online that you can get above 2TB drive to work in most PC’s if you buy a “Highpoint Rocket Card” however a quick look on eBay, Amazon etc and it isn’t worth the hassle given that these cards cost £30 plus. Because in my situation I’m left with no option but to have the drive external ( unless I pay £30 plus for a card and there is no guarantee this will work ) I decided to buy a good quality external hard disk caddy from Amazon, based on good reviews, this cost me apx £15 delivered. This is now going to be used as a second hard disk, externally.