HP Deskjet printer buying guide

It pops up when ever I press print. It started happening after I tried to print a webpage, and while printing, lifted up the top of the printer. The printer stopped as usual and now this message appears everytime although I have replaced the top, got enough paper, and the ink cartriges are filled.
Theres also a little orange light above a button on top of the power button that starts blinking after I press print. And it would not go off.
Please Help!
Computer OS: Windows XP Home Edition
Printer: HP deskjet 640C
P.S I’ve tried reinstalling the printer - didnt work

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