I get these codes on 7740. It is about 24 months old. B0003E4 appears with cartridges ejected but not removed and 007C9C98 appears when cartridges in. I can't take them out completely because the printer head is locked in place to the right hand side.
Be alert for scammers posting fake support phone numbers and/or email addresses on the community. If you think you have received a fake HP Support message, please report it to us by clicking on "Flag Post".