My Laptop used to discover my home WIFI but not anymore

Registration date
Monday October 8, 2012
Last seen
October 8, 2012

Hope that everyone is fine while reading this message.

I have a DELL Inspiron 1525 that used to discover, detect and connect to my home wifi network, but not now after I did the following:
1- I restarted the router using the router connection manager via "" to refresh the connection while it was down.
2- after I restarted the router, every Wifi device reconnected but not mine.
3- I changed device to review if the connection is net discoverable and sure it was.
4- I restarted the wifi and then the computer several times before going to "Manage wireless networks" and deleted it in order to reconnect.

Now i can connect through office network, my parents network, and every network except mine, in addition that my laptop discovers every network in the neighbourhood except the one 4 meter away form it.