Unable to start after installing real-time kernel

For some reason my browser is refusing to view the imgur link, And I don't feel inclined to force the issue given that you are newly signed-up user and this seems to be your first post...

How have you installed LinuxCNC, which Debian version? Which realtime kernel?

If you have a working Debian installation then you can try installing the realtime kernel separately, directly from the Debian repositories.

Search for linux-image-rt in the Synaptic package manager.

It might be worth trying the 2.8 or even 2.7 installer, then updating LinuxCNC as far as it will go.

Upload the pictures here on the forum, not on third party sites.
I can see the pictures, there is nothing useful there to troubleshoot.
If the PC gets stuck as in the picture and it does not go further, first thing i would check is the CPU cooling, then power supply, but first, try to boot Linux Mint on it, if this works then it would probably be something kernel/hardware related, so there are still options, easy ones, but if it does not = the PC is not OK.

DD can not get over a HDD password, but everything else, yes it can.
Now if windoze sets a HDD password when encrypting, that would be a nice reason to sue them for destroying your property.
That is to far fetched as that would require entering that password during POST, but UEFI can do that easily, so ... or it can use TPM...
I hate UEFI and Secure Boot (there is nothing secure about it) and TPM and....MS!