13 R3, black screen, backlight working and power button blinking

Hi, 

I have a refurbished alienware 13 R3 bought about 4 years ago. Recently, I went on a vacation for over a month and on returning found that the laptop was not turning on properly. Keyboard backlight was working, fans were full speed and power button was blinking. That's it.

I opened up the back and removed the battery (not just the cable) and did power drain for 30 secs. Turned laptop on....and nothing.

Power button is blinking in a 2,4 pattern which the manual says is a memory issue. Wiggled the memory cards around a bit but still no dice.

Not sure what to do at this point. My warranty expired last year so if it's a motherboard issue I don't want to pay the price of a whole new laptop to get this fixed.

Any idea what this can be and what else I can do to troubleshoot this?

Thanks in advance.