My laptop doesn’t seem to work unless it’s plugged in to the charger

Hi. I have a Windows intel laptop (Dell I think) that I mostly use for school and work assignments. It is not my primary computer so I’m not using it every day. I think it is about two years old maybe 3. I have noticed that when I try to turn it on, it is often unresponsive, and in order for the laptop to work, it needs to be plugged into the wall, even if the battery says it’s charged. Could the issue be happening because I don’t use the computer every day? I was wondering if there was a way to fix this or if I need to look into getting a new computer. Any advice is appreciated. Thank you.