step 5 done, if default means uncheck nothing then i have chosen default. no prompts for installing 3 help apps have appeared. now i shall continue to step 6. no 64 bit option is given.
step 23 result "This kernel requires an x86-64 CPU but only detected an i686 CPU. Unable to boot. Please choose a kernal appropriate for CPU." I have no idea what that says and no idea what i have done wrong and no idea what the solution is but i suppose it means i cannot do the next step.
What i wonder is why at step 9 there was no Ubuntu 64 bit or x86 option but only 32 bit although the iso file is x86. if the only option made available is Ubuntu 32 bit then surely the iso file should be x32 and not cx86? i hope you understand my totally unscientific English.
Hmmm, this is an unexpected problem. Although you may not understand what is happening, I think I do understand what you're saying.... VirtualBox is not giving you choices for 64-bit almost certainly because your copy of Windows 8 is a 32-bit version. (I have little doubt that your computer is 64-bit, but many manufacturers, like HP, would put the 32-bit Windows on them because it was a little cheaper).
In VirtualBox, your Windows is what is called the "host" system, and everything depends on the capabilities of the host. Because your "host" (Windows 8) is 32-bit... it will not let you install the 64-bit Linux Mint. If you are not running low on hard drive space, I would say not to delete the Mint 64-bit .iso file that you spent so much time downloading though... we may can use it again in another manner (to make a bootable DVD or USB, or to use it for a full installation). You can always delete the file later if you need the space.
By the way, "accepting defaults" means accepting the choices that are already picked for you.... in other words, do not change settings. There was nothing for you to change in the VirtualBox installation except to accept those other apps if they showed up. They probably did show up the first time you installed it, but after that they are not returning. There is nothing further to do about that... we'll just have to wait and see if VirtualBox works okay for you when you get a Linux to install in it.
And right now, we are a long way away from getting Linux to install.... because we got the wrong version (64-bit). If you still want to install Linux Mint in VirtualBox, it will be necessary to again download a huge .iso file.... this time the 32-bit version. And then, you will again want to verify the download like you did before, but you would compare to the 32-bit file that is shown in the checksum text file, sha256.txt. If this is what you want to do, then here is the link to get the 32-bit Linux Mint MATE .iso file (right-click on link and save to your hard drive):
http://mirrors.kernel.org/linuxmint/stable/18.3/linuxmint-18.3-mate-32bit.iso The instructions to install the 32-bit Linux Mint will still be the same as with the 64-bit.... except, of course, that you have to make 32-bit choices instead, such as what you saw in Step 9.
I am beginning to wonder if all this might be too much for you though? Or if maybe introducing you to Linux in "another manner" might be better, like I mentioned above? Do you have a DVD drive in your laptop? (And some blank DVDs?) One method is to use that 64-bit Linux Mint that you already downloaded and burn it to DVD a special way so that you can boot your laptop on the DVD and run Linux. Or a USB memory stick can be used instead of a DVD, but it will need another Windows program downloaded to put Linux Mint on the USB stick.
Anyway, these other methods are something for you to think about. Or you can go ahead and download the 32-bit Linux Mint file and we will try again with VirtualBox. Let me know which way you want to go, and I will keep trying to help you get started.
Cheers