I have been successfully using Inkjet Mall cartridges and inks for several years. Suddenly, the printer is showing all cartridges as not installed. I removed and reinserted the cartridges and then for a brief time two cartridges are indicating as uninstalled. When I remove, shake and reinsert these two, again, it indicates all cartridges are not installed. Any ideas? My 3880 is at least 6 years old, so may be in need of replacement.