If when you boot Windows 11/10, you see Non-System disk or disk error, Replace and strike any key when ready on a black screen, this post will help you.

I got a Non-System Disk or Disk Error when I booted up my 2 year old Compaq notebook. After restarting about 50 times over the span of half an hour, Windows eventually started successfully.

If you are only getting a "non system disk or disk error" message, I'd run some tests on the drive before dismissing it as bad.

But I removed the hard drive and connected to compaq system and it was not working. I formated the hard drive and installed Windows 98 again. When I reconnect to my HP system it is not working again.