its just a warning. Im not sure where since i dont know which windows you are using but i do know You can turn it off somewhere. In windows 7 i turn it off in the "action center: in my control panel, under notifications about my drives
It actually wont do any harm until you install or download something that wont fit, but even then it wont cause any harm to your pc. Whatever you are downloading or installing at that time will stop though. Then you will have to make space for any additions or downloads. But you could still browse the internet and run stuff already installed. If you made space right away though by either deleting files or uninstalling big programs it would help get rid of the annoyance.
TIP: delete some past restore points, they are usually large in size. Google it if you dont know what it is
Delete some files from the disk.
your laptop memory is almost full. Delete unnecessary files or if not, buy an external drive to store all important files so you wouldn't cloud up your pc
start with this article here > http://macpaw.com/how-to/startup-disk-fu…