Green upside down horseshoe blinking, won't print

SOURCE: printer stopped working after I cancelled a print job

1. Remove all print jobs at your computer
   
2. Turn off printer
3. Disconnect printer power supply
4. Wait 30 seconds
5. Reconnect printer power supply
6. Turn on printer
7. Try to print again, probably it will work now
   

SOURCE: HP Laserjet 2200dn print spooler unable to connect

Have you tried a different driver eg. rpcs or another version of pcl?Have you checked your workstations services app to check if your print spooler is running?Also when you print a config page from the hp it will give you your network details.To eliminate your network grap a crossover cable and connect directly to the printer and test.Let me know.

SOURCE: Network printing: can print test page, but not from apps (Word, F

Turn off advanced printing options under the printer's preferences or download updated driver from HP website.

SOURCE: My HP laserjet p2015n suddenly stopped printing.

You need to replace the formatter.

SOURCE: No printing; yellow and green lights are blinking together.

Check page 10 in the manual at this link:
http://h10032.www1.hp.com/ctg/Manual/bpd09384.pdf

Ifthe "Resume" & "Power" buttons & lights are the ones you referto, then here is a page explaining how to resolve this issue:
http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?lang=en&cc=us&taskId=110&prodSeriesId=71895&prodTypeId=18972&prodSeriesId=71895&objectID=c00681585