Printhead alignment failed

[rightcharlie]

I have a HP Photosmart Premium C309g-m printer/copier/scanner, that is about 2/3 years old, wirelessly connected to my laptop running Windows XP.
I recently tried to copy a document only for the printer to churn out a blank piece of paper. I know that all the ink cartridges are not empty (3 are genuine HP but magenta and photoblack are Jet-tec compatibles) but am aware that the printer is not used everyday.
Somewhat puzzled I ran a "clean printhead" operation thinking that the printheads may be a bit dry not having been used for a week. This had no effect. I have not at this stage used the deeper clean function that uses more ink.
I have recently had a paper jam in the printer and thinking this may have caused a problem, I then tried "Align the printheads". The printer eventually churned out a sheet of paper with a few faint ink marks on it but showed a message on the screen that said "printhead alignment failed". I have tried this 3 times with the same result. (Not unexpected I guess!). I have checked that there is no scrap of paper still stuck in the printheads.
Is there anything else I can do bar taking a screwdriver to the thing or is it terminally broken?
Many thanks folks.

[DaveLembke]

I'd take q-tips dipped in rubbing alcohol to bottom of ink cartridges, not enough to make a pool of alcohol just to be damp to clean ink off the piezo print head surface of the ink cartridge where the ink sprays out the bottom, and then dry the bottoms with a napkin or paper towel. Then insert the ink cartridges back into the printer and try again. Your printer likely has the blue laser that reads the paper after each pass of print head. It didnt detect the ink since there wasnt enough ink applied to paper and thats why it failed. If this doesnt fix this then you will need to replace the ink cartridges.

[rightcharlie]

Many thanks for your DaveLembke. What you have suggested makes sense. I will report back when I have got my hands on some q-tips and rubbing alcohol.

[rightcharlie]

I found a small bottle of compact cassette tape (remember those!) head cleaner labled isopropyl alcohol (another name for rubbing alcohol). It came in a handy dropper bottle which I have used to clean the heads. This seems to have made some difference but running the printer head cleaning operation seems to have eventually emptied two ink cartridges.
At the moment the printer head alignment is still failing but I suspect this is because two of the cartridges have no ink in them and hence cannot be "aligned" as DaveLembke suggests.
My next step is to buy some new cartridges (proper HP ones just to be on the safe side).
Many thanks to DaveLembke for his advice.   

[patio]

Generic cartridges cause this all the time...
If you replace them get the original ones.