A few of the reasons for a nonsystem disk or disk error include a corrupt boot-loader, a faulty hard disk drive, or a nonbootable floppy or CD present in the disk drive. To fix this, remove all external devices, such as CDs, floppy discs or USBs, and enter recovery mode.Continue Reading
Remove any discs, including floppies, from inside the disc drive, the USB slots and any other external drives. This is one of the most common reasons for a system disk or disk error.
If the above does not work, the next step is to fix the boot-loader. First, place your computer into recovery mode by using a setup CD or hit F7 as the computer boots up to access its advanced settings. Once in recovery mode, you should see a command prompt. In the prompt type, "fixmbr," and press Y to confirm. Finally, press Enter.
The computer's hard drive may be faulty when receiving a system disk or disk error. It may also be caused by the computer over-heating or by an issue with the system power supply ports. For these problems, it is best to visit a computer technician.