Did you try uninstalling the software, reboot and reinstall?
I have an HP Deskjet 3740 printer that is offline and won't print. The power light flashes continually. I looked at the HP support section and tried to follow the instructions. Nothing worked. I found another 3740 on craigslist which said it was never used and bought it. Same results! I am using an HP G70 notebook, with 3 GB of memory and Windows 8.1 OS. Any help will be greatly appreciated.