Why are all lights and LEDs blinking and the printer no longer responds?

there is a service manual that indicate your problem I found 1 looking on internet, here are the instructions to know the problem in the service manual

try this

Manual reset methods several EPSON Stylus Color. Actually there are two methods to reset epson printers counter, that is using software resetter such as adjustment program or SSC service utility or using manual by combination pressing button on the printer. If Reset using software resetter you can follow the way of usage the software but sometimes software resetter for the printer is not available. The only way to reset the printer if software resetter not available you can use manual reset.
The Following manual reset for some EPSON Stylus Color Printers:
1. EPSON Stylus Color
Pressing and holding ALT+FONT+LOAD+PAUSE buttons combination
press POWER button
Release all buttons
2. EPSON Stylus Color 300
3. EPSON Stylus Color 400, 600
Pressing and holding LOAD/EJECT and CLEANING buttons
press POWER button and hold it until you will see blinking INK OUT and PAPER OUT leds
Release all buttons
In 2-3 seconds time press LOAD/EJECT and CLEANING buttons again.
4. EPSON Stylus Color 440, 640, 740, 460, 660, 670, 760, 860, 880, 1160
Pressing and holding LOAD/EJECT and CLEANING buttons
press POWER button and hold it until You will see blinking INK OUT and PAPER OUT leds.
Release all buttons.
In 2-3 seconds time press and hold CLEANING button, until all leds will blink.
5. EPSON Stylus Color 680
Pressing and holding LOAD/EJECT and CLEANING buttons,
press POWER button and hold it until You will see blinking INK OUT and PAPER OUT leds.
Release all buttons.
In 2-3 seconds time press and hold LOAD/EJECT button, until all leds will blink.
6. EPSON Stylus Photo 785, 895
Pressing and holding Maintenance and Roll Paper buttons
press POWER button, You will see blinking Error led.
Release all buttons.
In 2-3 seconds time until led is blinking press and hold for 10-12 seconds Roll Paper button, until all leds will blink.
7. EPSON Stylus Photo 890, 1280, 1290
Pressing and holding Maintenance and Roll Paper buttons, press POWER button, You will see blinking Power led
Release all buttons
In 2-3 seconds time until led is blinking press and hold for 10-12 seconds Roll Paper button, until all leds will blink
In 2-3 seconds time press LOAD/EJECT and CLEANING buttons again.
8. EPSON Stylus Color 800, 850
Pressing and holding LOAD, CLEANING Color and CLEANING Black buttons
press POWER button and hold it until You will see blinking INK OUT and PAPER OUT leds.
Release all buttons.
In 2-3 seconds time press and release CLEANING Color button, You will see leds blinking.
9. EPSON Stylus Color 900, 980
Pressing and holding LOAD/EJECT and CLEANING buttons
press POWER button, You will see blinking INK OUT led
Release all buttons
In 2-3 seconds time press and hold CLEANING button for 10-12 seconds.
10. EPSON Stylus Color 3000
Pressing and holding PAUSE, LF/FF and DOWN ARROW buttons
turn on printer.
Release all buttons.

Reset your Printer by following these steps for your Printer Model:

EPSON Stylus Color 900, 980
Pressing and holding LOAD/EJECT and CLEANING buttons, press POWER button, You will see blinking INK OUT led.
Release all buttons.
In 2-3 seconds time press and hold CLEANING button for 10-12 seconds.
EPSON Stylus Color 3000
Pressing and holding PAUSE, LF/FF and DOWN ARROW buttons turn on printer.
Release all buttons.
EPSON Stylus Photo 785, 895
Pressing and holding Maintenance and Roll Paper buttons, press POWER button, You will see blinking Error led.
Release all buttons.
In 2-3 seconds time until led is blinking press and hold for 10-12 seconds Roll Paper button, until all leds will blink.
EPSON Stylus Photo 890, 1280, 1290
Pressing and holding Maintenance and Roll Paper buttons, press POWER button, You will see blinking Power led.
Release all buttons.
In 2-3 seconds time until led is blinking press and hold for 10-12 seconds Roll Paper button, until all leds will blink.

E5 means cartridges error - to fix press the "stop\reset" button for 5-7 seconds and then release it.

You can also try this:

1) With the printer power turned off but connected to a power source, while pressing the Resume/Cancel button, press and hold the Power button.
(DO NOT release the buttons. The Power LED lights in green to indicate that a function is selectable.)

2) While holding the Power button, release the Resume/Cancel button. (DO NOT release the Power button.)

3) While holding the Power button, press the Resume/Cancel button 2 times, and then release both the Power and
Resume/Cancel buttons. (Each time the Resume/Cancel button is pressed, the Alarm and Power LEDs light
alternately, Alarm in orange and Power in green, starting with Alarm LED.)

4) When the Power LED lights in green, press the Resume/Cancel button the specified number of time(s)according to the function listed in the table below. (Each time the Resume/Cancel button is pressed, the Alarm and
Power LEDs light alternately, Alarm in orange and Power in green, starting with Alarm LED.)

4 times----Green (Power)------Waste ink counter resetting

The blinking indicates that the drum unit is near the end of it's life. It will shut down soon and you will lose the ability to print until it is changed or reset.
To reset the drum counter. Press and hold down the white button (shown as blue in the image below) for about 4 seconds until all the LEDs light up. Once all 4 LEDs are lit, release the button.

Service manual says 3 flashing red leds = eeprom error (main digital / video pcb).
Suggest you start by implementation of Fujitsu Service Bulletin PDP 0068-01 Main Digital pcb see:-ttp://www.eserviceinfo.com/download.php?fileid=43450

My cannon printer no longer responds to any commands. I get 4 yellow blinking lights and then 1 green blinker.

Here is the manual:
http://www.smc.com/index.cfm?event=downloads.doSearchCriteria&localeCode=EN_USA&knowsPartNumber=false&productCategory=1&modelNumber=969&partNumber=1830&downloadType=8&os=0

Is the unit working?
Which lights are blinking?