I think you have a virus checker that is running at the same time every day. that happened to me with AVG virus checker. It looked everyday at the same time at the hard drive. Each time it kicked off the printer and I had to reboot. I had set AVG to run every week but it does some other checks everyday. The computer was running XP. Same with another computer running StopZilla but that was once a week. All Win 7 systems do not have a problem and I use the MS system that came with the program.
The key was turning off the ink status for me and adjusting the virus checker times. I agree that the problem still resides with HP and they should fix it but until then we have to find work arounds or send the printer back.
Can you make sure that the computers that work or on the same OS as that that doesn't work and do they have the same virus checkers?
gdollar