Thanks for your reply.
Sorry, my question was not clear.
My computer is a Macintosh All in One (AIO), 64 bit, running the Apple OS called El Capitain(latest vesion 10.11.3. This type of computer has all its working parts enclosed in its monitor casing, and is very neat....no black box + monitor...no cables at all! Tidy.
However, its not as excellent as Linux Mint 17...it has its own "Apple" limitations!
I have been a user of Mint for years, and wish to dual boot the Imac AIO with Mint 17. As this computer has no CD/DVD optical reader, it needs to read from a pen drive, and I will need to repartition its drive. I have looked on the net for help, but , any "how to" seems beyond my understanding.
Can you help?