Operating system missing Windows XP

I encountered this issue when I finished rebooting the computer.
The old operating system that has been installed was Windows 98, and I installed a new Windows XP but when I start the computer after rebooting the computer, the flash message on the screen remains as "Missing operating system" .

I checked the boot devices, and it is placed correctly. I restarted the computer again but still the issue came out. I reinstalled the operating system, and it normally run, and loads the OS. Turned the computer on and waited for a couple of minutes, but then again the issue still lingers.
Can anyone help me with this?
Thanks
