Welcome to Justanswer.com, my name is Dustin.I'm sorry to hear about the issue you are having, I will do my best to help you resolve it.
When you say you are trying to load 5x7 paper.. You must be trying to use the paper casette shown in this picture.
When you slide the guide back, does the 5x7 paper fit in the machine in between the guides?
If so, then we may just need to tell the machine to print from a different paper source.. heres how to do that
Go into your printing preferences and then change the paper size and paper source if needed, as shown on page 9
That will tell the machine to use the correct tray, with the correct sized photo paper in it. If you get stuck or have any further questions, let me know!
I strive to provide great service, and greatly appreciate a 5 star rating clicked and submitted when you are satisfied. If you do not submit a rating, I am in no way credited for my time. I always answer follow up questions.Dustin S.Senior Technician and Network Switching Systems Operator / Maintainer.