What does it mean invalided sistem disk?

"Invalid system disk" is an error message that typically indicates that the computer is unable to locate a valid operating system on the disk it is trying to boot from. This can occur due to various reasons, such as a corrupted operating system, a missing boot sector, or issues with the hard drive itself. It may also indicate that the BiOS is set to boot from a disk that does not contain a valid OS, or that there is a problem with the physical disk or connections. To resolve this issue, users may need to check their BiOS settings, inspect hardware connections, or use recovery tools.