My HP Deskjet 3940 Printer's My printer is offline...?

My HP Deskjet 3940 Printer's  My printer is offline...? 

My HP Deskjet 3940 Printer's status is coming to be offline and thus it is not printing any document.. 
What should I do? 

Best Answer:  All the drivers and utilities that are necessarily required for the HP printer to work smoothly under minimal errors shall be installed in the computer before trying to set-up a printer. The users are therefore advised to verify the printer drivers and utilities and reinstall them with their most recent versions by downloading the newest versions from the original HP support website. Doing so and reconnecting the printers will help in solving and preventing offline errors in your System.

For XP  My HP Deskjet 3940 Printer's  My printer is offline...? 

Start
Settings
Printers and faxes
Left click the printer icon
Click the word printer
Remove check from use printer offline, and make sure it is set as default printer

For Windows 7 My HP Deskjet 3940 Printer's  My printer is offline...? 

Start
Programs
Devices and Printers
Right click the printer icon
Click see what’s printing
Click the word printer
Remove check from use printer offline
Make sure it is your default printer