BootCamp in a death loop

Hello,

I am trying to install Win 7 on my Mac Pro (mid-2010, OSX 10.9). Managed to persuade using an ISO image BootCamp Assistant (not really any help to me so far!) to partition my HD and it rebooted. Idiot that I am, I had two DVDs in the Mac Pro, one containing the Win7 ISO image and the other an old XP DVD. MP seeks to start from XP DVD but that does not recognise the partition and I cannot repair it. I've tried restarting the machine with the option key so that I can select my OSX boot disk and try again but the screen goes blank, the mouse pointer is seen (but I cannot control it) and none of the drives appear. I have also tried to restart using the C key with my Apple tools CD but that refuses to work too (I just get text that looks like Windows at top of black screen telling me I have no bootable disks).

Any idea how I can break this death loop please? How do I get back to my boot disk so that I can get into OSX?

Many thanks for any help.

Regards,

Simon.

PS
I can use my lecturer discount to download a version of Win8.1 Pro Student from MS themselves but not sure if I do this on another machine, put it on DVD, and restart the MPro whether that will work either!

Message was edited by: Axtron