Blocked nozzles can be caused by powering down the printer incorrectly... Make sure that you turn off you printer at its power button rather than powering off the power supply. Check you manual for the buttons to clean your printer, or if you are running windows, select printer properties, select utilities, and then clean printheads.
If you have got MS Word go to file ----> print----> proprties ----> Utility ----> Head Cleaning(H) This will work with any software I just used MS Word as an example. Also if you use cheap ink cartridges this could cause the problem I use JET TEC or the original no problems up to now.