Power light keeps flashing and the printer does nothing else. No printing, communitcating with PC.

"All lights blinking and printer not responding" is indicative of serious ink cartridge issue. Usually when this happens the printer fails to goes through the motions of the printing process, kind of stands still with indicator lights just blinking away. This could be as a result of either of these scenarios.

The Solution is to try an older/another cartridge (doesn't matter if ink is finished. You must replace cartridge one at a time). If lights stop blinking it confirms that your cartridge has become incompatible or developed incompatibility. Also if your printer is the type that can work with only one cartridge, remove one after the other (closing back the lid/cover) to determine which in the set (black or color) has become incompatible. At the instance the incompatible one is removed and you close the lid, the blinking will stop (for printers that can print with one ink cartridge only). Just replace the incompatible one and start printing again. In most cases the issue is always with one cartridge. But if both are affected, you have to replace both. Because of this type of problem, always keep used cartridges somewhere safe; they come in handy for this type of troubleshooting.

The electronic panel on the cartridge that makes contact with the cartridge carrier inside the printer is dirty and needs cleaning. This electronic panel is front part of the cartridge with copper "dots".

The Solution is to try to clean this panel with a piece of folded tissue paper soaked in a bit of methylated spirit. Also try to clean the area in the cartridge carrier/holder that makes contact with the cartridge's electronic panel (Usually this is more difficult). If you cannot reach it with your fingers, use a stick or something with tissue wrapped around it. Allow to dry well and return the cartridges, close the cover. The blinking should stop if the electronic panel is the issue. Once the blinking stops the printer will print.