I am using Windows 10 and IDE 1.8.8. I plugged in the arduino mega 2560 pro mini and it did light up the LED however I didnt get any response from the pc and I opened device manager still no connection shown. Could anyone please help me? Thank you.
Try other cables, USB 2.0 ports, Make sure nothing else is connected to the board, and make sure you can see COM & LPT ports in device manager.
If nothing shows in device manager you may have a broken board.
Definitely try other usb cables, there are a lot of that type cable used on phone chargers, and to save a tiny amount of money the manufacturer only puts in the wires for power and ground, so you can't send data through the cable.