Acer AT350 F1 - Manual (Page 122)

5 System troubleshooting 110
Verifying the condition of the storage devices
As POST determines the system configuration, it tests for the presence
of each mass storage device installed in the system. As each device is
checked, its activity indicator should turn blue briefly. Check the
activity indicators for the hard drive(s), DVD-ROM drive, and any other
5.25" device you may have installed.
If any of these indicators fail to light up, refer to related problems
listed in the Specific problems and corrective actions section.
Confirming loading of the operating system
Once the system boots up, the operating system prompt appears on
the screen. The prompt varies according to the operating system. If the
operating system prompt does not appear, see "No characters appear
the display monitor" on page 113.