Error Message: Status No print cartridge - Install the print cartridge

defective sensor switch, print cartridge or HP LJ programming.

do you have another cartridge that you can install?
How about blowing compressed air to remove dust particles.
run self-test diagnostics and see what the printer says.

Did you try unplugging it for a few minutes to see if it would clear?

let me tell you something 1st at all the hp website has a greet support so see this :
http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?lang=en&cc=us&objectID=c00062142&prodTypeId=18972&prodSeriesId=378060
http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?lang=en&cc=us&objectID=c00063128&prodTypeId=18972&prodSeriesId=378060
http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?lang=en&cc=us&objectID=c00063127&prodTypeId=18972&prodSeriesId=378060#N10011

This error sometimes occurs if you use an aftermarket, Non HP, or refurbished/refilled cartridge.

Toner cartridges have contacts that allow it to communicate with the printer and this is how the printer knows how much toner is left, if it's legitimate (HP) cartridge, ...  As indicated above by irwinpks Cleaning the printer, testing with another cartridge and printing a test page are Excellent Ideas.  A concern as indicated by jonoakley is to not use refurbished/refilled cartridges.  HP won't talk to you about a problem which may be created by anything other than original HP parts and consumables.

Just a thought:

In the past HP had some model printers with Toner Cartirdges which had a wire that would short and burn out the first time it was put in the printer.  That short would reset the toner information.  Doubt if they would return to this nasty little process But might look around to see if two metal post appear to be sticking into the toner cartridge when firmly installed.  
- Ihad this issue once and when I talked to HP they just said nothing could be done except replace the cartridge.  Talked for a while longer and they explained what likely happed and said to short with a paper clip.  Problem Fixed.

Hope this Helps!!!

I have tried doing a full cleaning of the unit and changing cartridges 3 times....Still the same problem...

Any other ideas out there..?

Thanks,

Scott

accept my last comment...all fundamental troubleshooting is exhausted.

:-)

Seems your problem hasnt been fixed. I see a refund in the making

@jonoakley..."Seems your problem hasnt been fixed. I see a refund in the making"

A broken printer is deemed an answer to the question. Since we've exhausted basic troubleshooting technique, the only recourse is to send the printer in for repair.  That suffices the question posed "Can anyone provide any ideas, advice or feedback...?"