Laptop keeps disconnecting from wifi?

I have an hp laptop.. Not too old but it's not brand new either. For some reason every time I am on it, the wifi disconnects and I am not able to reconnect unless I restart my laptop. I know it's not a problem with the actual wifi because everyother laptop and phone is working perfectly. The problem is that the laptop does not have a battery life so it will just turn off if you unplug it...
Please help, this is extremely frustrating!