Canon S400 Reference Manual page 205

Check 1
Is the printer switched on?
Check the POWER lamp to see if it is lit green.
If the POWER lamp is flashing green, the printer is warming up.
After the POWER lamp is lit, the printer is ready to use.
Check 2
Are the printer and computer connected properly?
Check the connections of the printer cable at the computer and the printer.
Check 3
Is print spooling operating correctly?
Cancel spooling and send the print job directly to the printer.
1
Open the Printer Properties dialogue box directly from the Start menu.
2
Click the Details tab and click the Spool Settings button. Click the radio
button for "Print directly to the printer".
For details on how to open the Printer Properties dialogue box directly from
the Start menu, refer to the Driver and Utility Guide for Windows Users.
Error writing to LPT1 or USBPRN
Troubleshooting - An Error Message Appears 205