Post the Kernel Panic report. It's either in /Users/username/Library/Logs/PanicReporter/ or in /Library/Logs/PanicReporter/. In the meantime see
About kernel panics,
Technical Note TN2063: Understanding and Debugging Kernel Panics,
Mac OS X Kernel Panic FAQ,
Resolving Kernel Panics,
How to troubleshoot a kernel panic, and
Tutorial: Avoiding and eliminating Kernel panics for more details.
I wish I had the time for all that. it's going to take forever. I couldn't find the panic report, there wasn't one, in either location.
The computer came with no disks, it's second hand, it had ML installed on it, I decided to partition the HDD to install SL myself, but I cannot boot from anything, not CD, USB, or anything. I tried to use the AHT (Apple Hardware Test) but it wasn't designed for my system apparently, but my computer is from 2011, not 2013
I am thinking of installing a clone of my old computer and then just upgrading to ML manually. But, am not sure if I can do that, what if I have a hardware problem?
It's so annoying, I can't boot from CD or USB, I've never encountered that before, I hope it's just a software issue. I notice in the sidebar that the person did a Carbon Copy Cloner and they might well have done it wrong, but how do I do a clean install???
If your old machine has 10.6.8 one it, make a bootable clone to an ext HD, and try booting the iMac with it. If your second hand iMac is a mid-2011 one, it should boot with 10.6.7 or later. Details on the machine. BTW, if you bought it w/MLion installed, then most likely it's registered to the previous owner's AppleID and you need to wipe the machine and get it registered to yours. If it is a 12,2 model, then that's why it won't boot with the retail SL insall disc. We need more info.
Normally I would persue this but I just don't have the time, so I am just going to give up on it, not my usual style at all!
I booted with FW and managed to select some kind of Revovery partition, I don't know how that got there but it allowed me to restore from Time Machine and so I managed to get my old system up and running. From here I am still unable to boot from an external HDD, same thing happens, but everything else is the same.
So, I am just going to cut my losses and just keep trucking until, in a year or two, I can afford a Mac Pro, the new one, the toilet roll one, and just wait until then. Everything else seems to work, so it will hopefully be okay??
Thanks for everybody's help, I don't know why I'd have to worry about any of this, strange behaviour!