Find out if there's problems with the laptop WIFI or router's WIFI.

Somethings to consider:
1. Some wifi adapters don't work well with certain routers.
2. updating your wifi drivers
3. updating your router's firmware
4. try connecting on a lower speed setting on the wifi adapter (example: g speed, etc)
5. does it work on other wifi routers?

A lot of it is trial and error to see what the real problem is. I do not recommend doing all of the suggestions at the same time. Try out different combinations until it works.

Good luck.