My printer is printing graphics with a yellow tint, Print is fine.

Hi,

My HP Printer has just started printing images with a yellow tint. The text is fine, but both a photo and a piece of clipart has this additional yellow tint to it (I have also tried a different image from a different piece of software). It was fine yesterday and has just started now (I need to print some birthday invitations). I have selected the correct card stock and turned printer off and on, but still have the same problem. However, I also can't work out how to print a test page.....well that's not true, if I click on print test page it prints a page of black print with a very tiny windows logo that doesn't prove anything. I can't find how to print a colour test page. I have Googled the problem and on an HP forum it gives instructions of how to do it, but the options suggested are not visible. Argh!!! Help please.