How do connect my laptop to my works wireless?

My sister's laptop won't connect to the wireless, but everyone else's works?

• My sister doesn't live with us, so her connection to our internet isnt always connected, but has worked for her in the past. She came over and tried to connect, and it says she's connected to our wireless internet, but it says she has no internet access. down in the right hand corner where it shows the connectivity, theres a little yellow triange with a ! in it. there are three other laptops in the household that work excellent with the wifi, but for some reason hers doesn't and we can't figure out why. she's tried disconnecting, reconnecting, restarting the computer etc. Anyone know how to fix this?

• Answer:

  Ok, lets try an elimination process to connect to the internet: First lets make sure your Laptop at least lists existing networks. -Lets remove your Router's Network from current list of network listed on the laptop so we can establish fresh connection. Click on your wifi icon in the taskbar Click Network and Sharing Center - Click Manage Wireless Networks.. Select you network and click remove... then try to reconnect by entering the WPA (Wi-Fi Protected Access) or WEP (Wired Equivalent Privacy) key/password. -Most laptops are equipped with a manual slide/push/press switch on the front or side of the laptop that turns the wireless adapter on or off. Sometimes, we accidentaly push/press this button and turning wifi off. -Most laptops comes with the software version of adapter switched (enabled or diasabled in 'Device Manager'). - Sometimes Internet security interefers with web connection. Disable your security for a few mins as eliminatation process and trying connecting. Good luck