Try this...
- Right click on the background of your desktop (not on any items).
- In the menu that shows, click"View".
- You should get side menu listing the size of icons as well as how they are arranged.
- Select the size you want.
If this doesn't resolve it, try...
- Reboot (turn it off and back on) the laptop. This may resolve it.
- Try using "System Restore" to set the computer back to the most recent restore point, prior to the problem starting. It is possible an install, update or new program made the changes.