Hello David - and welcome to the Forum.
Mint 18 is rather old now and if your laptop is
very old then this combination might be the source of your trouble.
If your laptop is 64 bit with reasonable memory then I recommend that you install the latest version Mint 20. The recommended system requirement is:
1GB RAM (2GB recommended)
15GB of free disk space (20GB recommended)
1024×768 resolution
You can download it here:
https://linuxmint.com/download.php.
There are three versions available:
Cinnamon An edition featuring the Cinnamon desktop
MATE An edition featuring the MATE desktop
Xfce An edition featuring the Xfce desktop
Try them all using "Live USBs" to choose the one that suits you the best. If your system is 32 bit or lacking memory, then please let us know the laptop's make/model/memory and I'm sure someone here will be able to advise you.
Keith