Not knowing what model or brand, I would suspect that the Print Head is clogged. The ink from the Carts. is channeled to a thing called the print head. This is where the ink is transformed into print patterns and sprayed on the page. Often (some HP is an example) the print head is a removable, replaceable and cleanable item. Your printer software tools may have an option to clean the head. Check your printer documentation (online if you did not save it somewhere) to check on this. The indicator is flashing I suspect because even with a new cart. the ink is not flowing to the head sensor so the unit thinks there is no ink.