Q: indicator light and battery light both are blinking

Just to get this clear:

After your laptop gave a memory (RAM) error you swapped out your ram for a working RAM stick and then your indicator light and battery light are blinking and your laptop will not start?

Have you tried an SMC reset and an NVRAM reset?

You could also try to start up while holding down shift to get into safe boot mode and see if that works.

Hope this helps!

You can try running the Apple Diagnostics -> Using Apple Diagnostics - Apple Support

You can attempt it:

1. Press the power button to turn on your computer.
2. Immediately press and hold the D key until Apple Diagnostics begins.