the chip is faulty on the black cartridge, change the black and it'll work, alternately you can out it diagnostic made and run without the cartridges being monitored
Follow these steps to remove previous HP drivers, and then install the new driver.Step one: Remove previous HP drivers
Follow these steps to remove the current drivers.
Disconnect the USB cable from the HP product, if it is connected.
Click the Windows icon (
), and then click Devices and printers
.
Find the printer icon (
) representing your HP product, right-click it, and then click Remove device
.
Follow the on-screen instructions to remove the driver.
Repeat these steps to delete multiple instances of the same printer icon, and also for any fax icons for the product.
Reboot your computer.
When your new operating system is up and running, simply connect the USB
cable from the computer to the back of the HP product, and then press
the Power button (
) to turn it on. Windows 7 detects the hardware and automatically installs the correct
driver. A notification lets you know when installation begins and when
it is complete. You do not have to download any software or insert the
product CD.
This problem is caused by Mopier Mode being enabled by default. The idea of Mopier Mode is to minimise computer and network traffic by sending only 1 copy to a printer equiped with suitable internal memory. That stored copy is then used to produce the multiple copies. Most HP Laserjets do not have suitable internal memory and so only the one copy sent by the computer gets printed. To disable Mopier Mode:
Click Start
Click Devices and Printers
Right click your Laserjet Printer
Select Printer Properties
Click the Device Settings Tab
Scroll down to the bottom
If necessary, expand Installable Options
Click on Mopier Mode
Select Disable in the selection box that appears
Click Apply
You will now get multiple copies.
If the device does not work after turning on the printer, it is due to power failure
But if the device rotates, either the laser is faulty or the fusing thermostat is broken.
Hello,
A couple of things to check.
1) Make sure the paper guides in the tray are adjusted correctly for width and in particular the length.
2) Remove the tray completely check guides.
3) Make sure the tray is fully seated into the printer.
4) Make sure the paper in the tray matches the size of the guides.
If the guides and paper seem OK, the printer may need servicing by authorized service center.
41.3 UNEXPECTED
SIZE IN TRAY [xx] alternates with LOAD TRAY
[xx]: [type] [size]Description
This is typically caused if two or more sheets
stick together in the printer or if the tray is not properly
adjusted.
Did you remove the sealing tape?
5. Remove the new print cartridge from its packaging, remove the orange cover from the print cartridge, and then pull the orange tab straight out to remove the sealing tape.
6. Squeeze the blue release levers on the print cartridge, holding it with the roller facing you. Lower the cartridge straight down into the carousel until it is firmly in place.
7. If you need to replace another cartridge, close the top cover and the scanner assembly, press ROTATE CAROUSEL, and then repeat steps 4 through 6.
http://www.hp.com/ctg/Manual/c00292207.pdf
Other ideas
https://www.google.com/search?q=Hp+laserjet+2840-yellow+cartridge+flashing
..
), and then click Devices and printers
. 
) representing your HP product, right-click it, and then click Remove device
.
) to turn it on.
