This is a fairly common error on HP printers caused by malformed PostScript documents. If a printer shows a "79 Service Error" (a common error to HP printers) on the LCD display, do the following:
- Locate the on/off switch on the bottom of the printer.
- Toggle the switch to the off position and COUNT to 10.
- Turn the printer on again and the system should be all set.
If a print job of yours repeatedly causes this error, it may indicate a problem with the print job. Try breaking your document up into smaller chunks before printing it.