Dell Latitude E6420 Doesn’t Boot, Charger LED Blinks 22 Time

My dell latitude e6420 faced blue screen n said it is doing memory dump then shut down.

I power it on n it reached to the boot options,

– Start windows Normally
– Run a startup diagnostic (its the meaning, not the exact wording as I don’t remeber it now)

As it recovered from blue screen, I chose 2nd option n laptop booted again n showed a blue screen error just within couple of seconds I pressed the power button.

Since then laptop is not booting. Power button LED goes of in 3secs n LEDs on the left upper corner of keyboard are,

– Storage LED is solid
– Charging LED blinks 22 times before all shut down
– Wifi LED is solid, even if I turn off the Wifi hard button

Went through lots of suggestions over the internet n Have done below so far,

– Cleaning connectors of HDD n RAMS n Wirless cards etc… n reseating one by one in various pattrons

– Removed CMOS for over suggested 10 minutes n cleared static charge as well

– Same behavior after each step

Please advise…