i got a problem with my nexus 5 which is pure stock and unrooted . i think it was a SOD,the phone was turned off automatically . i charged it for next 5 hours. but still it doesnt boots up. i have gone through this and this links for help. Following the second link by pressing volume down and power button the phone wont enter bootloader mode. But when i connect the phone to a pc while pressing the key combination it enters the bootloader mode for a second and switch off then turn on again to bootloader and this cycle continues. Bootloader mode is not standing there permanently for flashing again too. also if i connect phone to a charger it keeps on showing google logo and then turn off and again this cycle continues.
Any help to this issue is welcomed.