Pixma MG7550 won't print

[SJ]

Hello

My Pixma MG7550 stopped printing half way through a page and now won't print anything, pages are blank.  Since this happened I have installed a new modem which is connected and working fine.

I've deleted the drivers and software and reloaded them, I've checked the spooling thingy, i've checked the cardtridges - they all have ink in them.  It's switched on.  The scanner works.

Help!

thanks

SJ