i am stuck in the initramfs shell. Message is no valid partition table. I have run fsck on the drive many times and still same thing. ‘Is there a way to format the drive and then install OS? I dont mind loosing data on the mini as it is backed up.
thanks
If you install an OS (like Debian or PureOS or Fedora or whatever) from a USB stick, then I think the installer program will give you the option to format the disk.
LiveBoot.
You can investigate the problematic disk more comprehensively. You can format it. You can install on it.
Of course if you have a true (disk image) backup then you can also restore the backup from LiveBoot. That might be preferable to formatting and/or reinstalling.
If it’s actually a failed or failing disk though then none of the above is really great because it’s not addressing the underlying problem.
You can’t run fsck if you have an invalid partition table. fsck can only check a file system that it can find and without a valid partition table it probably can’t find any file system at all. Bear in mind that for almost all environments, you run fsck on a partition not on the whole disk.
Of course it is also possible that there is nothing wrong with the disk and the disk content just got corrupted by something privileged writing to it.
It may help to say what disk technology type is involved.
If it were my disk, I would immediately use LiveBoot to image the entire “failed” disk to an external disk. Then I would start troubleshooting.
How deeply do you want to go into this?
Since all the data is on my nas i going to try and just install new OS. I think it got corrupted when we lost power. If that does work then i will try something else 
i can boot USB…tried two diff distros and after getting to install screen it just stops almost like its locked up…just hangs and only thing to do is hard stop any thouyghts?
Temporarily remove internal disk? (LiveBoot shouldn’t care that there’s no internal disk, and that will fault isolate the internal disk.)
If you had the needed enclosure, you could also put the internal disk in an enclosure and try it on a different computer (if you have another Linux computer).