I troubleshoot and fix home and biz WiFi all the time. Here's the usual fixes.

1. Install the latest firmware in the router.
2. Do the WiFi channel check with my Android phone and a WiFi scanner.
This is not an offer to teach how to use or interpret.
3. Check with my own laptop the WiFi spots work.
4. Fixing a cranky laptop is its own discussion. But if the WiFi is bad in the laptop we try some USB WiFi stick.
5. If the router is bad, replace.
6. If the distance is over 30 feet we install a WAP.