invalid system disk

[Urocyon]

HP displays black screen with error msg:  invalid system disk replace the disk, and then press any key.  I can access the bios menu and start up menu...changes I have made have not solved the problem.  Posts regarding the issue are dated 2013.  I am  hoping for someting current.

[BeemerBiker]

Windows boot manager cannot find the operating system. 

Is the disk drive listed in the bios?  Is there more than 1 hard drive?

If the WIndows 10 OS was on a "Western Digital" make sure that disk is the primary boot and not "Kingston" or the M.2.  Also vice versa.

If the bios indicates it is trying to boot the correct drive then you need to so a startup repair.

Did your system come with a DVD with win10 on it?  Did you make a DVD or USB boot with windows 10?   Got a "recovery" flash drive?

If not then download or borrow Windows 10 and run the startup repair. 

Post back here if a problem.

download tool https://www.microsoft.com/en-us/software-download/windows10

[Urocyon]

I am using a recovery disk; start up repair "couldn't repair your computer"; system restore needs the windows installation; image backup cannot find an image.  I have cmd prompt if that is a route (?).

[BeemerBiker]

Not good. I had that happen on a win10 ->11 upgrade as explained here 

I as able to recover by switching from secure boot to legacy boot.  If this works for you post back here.

If not, then try the "custom install" where you install win10 without deleting anything. as described here

https://answers.microsoft.com/en-us/windows/forum/all/how-to-perform-a-custom-installation-of-window...

I think you have done the "repair" so what is left is the upgrade install keeping files, etc.

If you get a warning that the partition contains data which will be deleted then you have selected the wrong upgrade.

[WAWood]

@Urocyon 

This issue is often due to a failing drive.

So, let's check that first, because if it is failing, it would need to be replaced and there is no point then in doing anything else until we confirm that.

If your PC is new enough to support UEFI, you can use these steps to test the HDD (Hard Disk Drive): http://support.hp.com/us-en/document/c00439024

If not, to check the HDD you have to follow these steps:
1) Press Esc key repeatedly, several times a second, while rebooting the laptop. Do NOT hold the key down, just press it over and over.
2) Eventually, you will see an HP Startup Menu
3) Press the Function key for testing the hard drive (usually F2) and let it run.

If the drive checks out OK, then report that and I can provide you options for reinstalling Windows on your PC.

Please note that if your model has an SSD instead of an HDD, these diagnostics might not work properly.