Since it still has warranty, I'd have it repaired for free. They might say it's caused by a defective USB device that you connected and won't be free, so better be sure that powerbank doesn't hurt other PC's or laptops.
Today morning, i plugged my laptop for charging. Bulb was glowing, indicating it is charging. I turned on my lap and also its turned on. My friend plugged his power bank to my usb port for charging. No screens are showing on display, so i pressed power button again. Now my laptop wont start and even when i plugged, laptop doesnt show charging.
1. I tried resetting by pressing power button for 30 seconds.
2. I tried another charger.
P.S: my laptop is ASUS X540L. I brought laptop 3 months ago.