Why does the power light on my HP E221 display flash white? The screen won't turn on and there is no response from pressing any of the buttons on the front.

A white computer screen can appear sometimes if your graphics card is bad . If the computer screen turns white as soon as you press the Power button that's a good sign that there something is wrong with the computers graphics card.
Try Pressing Ctrl + Alt + Delete.on the keyboard for your computer or try to reboot your computer too. You can fix the white screen issues here by simply using a keyboard shortcut. Try pressing Ctrl + Alt + Delete all at once then when the white screen shows up.

Contact hp servis

step one, big battery out? skipped that?
step 2, a good power pack , that means 19vdc on those 2 pins.
bingo BIOS screen now work ,yes?
step 3, try an external VGA screen at the P15 VGA jack there
screens work now (BIOS first) yes/no?

remove DVD, drive
and all USB devices
there booting with only 1 memory stick. (got more?, try each 1 by 1)
black screens of *****'.

the lack of flash codes, Implies Power pack is dead. or CPU overheated, and selfshuts down. that fan going dead tells
me the power park is dead.

http://pcdied.com/#black-screens

the scan function won\'t work on my HP Deskjet F4280. When I press the scan button, all that happens is the light on the power button starts flashing. Any assistance would be much appreciated

Check This URL out from HP. It will help you.
Compaq Presario CQ50-100 Notebook PC series - HP Notebook PCs - Troubleshooting Black Screen Displays with No Error Messages During Startup or Boot - c01997899 - HP Business Support Center

hi you can try these steps:

1. Turn the product off.
2. Unplug the power cord from the product.
3. Wait 30 seconds, and then connect the power cord to the product.
4. Turn the product on.
5. Make a color copy by pressing the Start Copy Color button on the control panel.

• If the copy job is successful, you do not need to continue troubleshooting.
• If the error message displays again, proceed to the next solution.

2)

1. Disconnect the power cord from the product.
2. Press and hold # and 3 while reconnecting the power cord to the product, and then release both buttons.
3. Try making a color copy by pressing the Start Copy Color button on the product control panel.
   • If the partial reset resolves the issue, you do not need to continue troubleshooting.
   • If the error message displays again, proceed to the next step to try a semi-full reset.
4. Disconnect the power cord from the product.
5. Press and hold # and 6 while reconnecting the power cord to the product, and then release both buttons.
6. Try making a color copy by pressing the Start Copy Color button on the product control panel.
7. the # and 6 will reset the whole printer as it is factory, I hope it will work fine!!Best of luck!!

OK I had the hp error code some problem and here is the conversation I had with the tech...
James Cowan: HP error code 0xc18a0001
Earnest: I will assist you in this regard. I understand that a error code with 0xc18a0001 with "Ink System failure" is displayed on the front panel of the All-In-One printer. Am I correct?
James Cowan: Correct
Earnest: May I have the model number of All-In-One you are using?
James Cowan: c6250
Earnest: Please let me know the room temperature in which printer is replaced
James Cowan: 67 degrees F
Earnest:: OK. Please perform the below steps on the front panel of the printer to resolve the issue
James Cowan: OK
Earnest:: Press and hold the "left arrow" key. Press the "Setup" key and release both keys, display should say "Enter Special Key Combo". Press and release the "OK" button
Earnest: Please ignore the above steps
James Cowan: OK yes nothing seemed to do anything
Earnest: Please perform the below steps on the front panel of the printer. Press and Hold the "Print Photos" & "Red Eye Removal" buttons. Release both buttons. Display should say"Enter Special Key Combo". Press and release in sequence"Red Eye Removal", "Print Photos", "Red Eye Removal"
Earnest: Display should say "Support" and display the FW rev (something like R0616R)
James Cowan: COxxFN0723BR
Earnest: OK. Press and release the right arrow button until the display says "System Configuration Menu"
James Cowan: OK
Earnest: Press and release the "OK" button
James Cowan: OK and it says hardware failure status
Earnest: Display should say "Hardware failure status: Clear. Press OK to clear". Press and release the "OK" Button. Message changes to "Hardware failure status Cleared. Press Cancel to continue". Press and release the "CANCEL" button as many times as necessary, so that, either the "Welcome to Photosmart Express" screen appears, or, the "Ink System Failure" screen appears. Please do not try to print at this stage
James Cowan: OK
Earnest: Using the Power Button, turn the unit OFF and unplug the power cable from back of the printer and wall outlet. Let me know once you are done with the above steps
James Cowan: OK its unplugged
Earnest: Wait 30 seconds for the power to get discharged and then plug the power cable into the wall outlet first and then into the back of the printer. Turn the unit on. The printer may display message "Use POWER button to shutdown the printer" followed by "Press OK to continue". Press OK
James Cowan: OK
Earnest: Let me know the message displaying on the front panel of the printer
James Cowan: printer preparation occuring - do not interrupt
Earnest: OK
James Cowan: OK its done
Earnest: Let us print a self test page from the printer now
James Cowan: OK deal
Earnest: 1) Load letter, A4, or legal unused plain, white paper into the input tray
2) Make sure that the printer is on and loaded with unused plain, white paper
3) Press Setup. The Setup menu appears
4) Press the down arrow button to select Tools and then press OK
5) Press the down arrow button to select Self-test Report , and press OK. The self-test report prints
James Cowan: OK printing
Earnest: OK, please check whether all the colors pritned perfectly on the test page
James Cowan: Perfect
Earnest: Great... Cheers!!!
James Cowan: Thank you very much
Earnest: Now you can continue using the printer.

hi, if ur screen turns white, it could be any problem starting from ur LCD to motherboard or as u said a virus. to assist u in a right way i need to know what exactly is happening between that short duration between pressing the button and white screen. most importantly is anything else comming up on the screen before the white screen.
cheers

ok, get to the event where you get this to happen "...then turn it back on the monitor does come on normally...", but just after power-up, press the F8 key to go to safe mode. If nothing visible, press ENTER anyway...get to safe mode yet?