Wireless Internet forum: Linksys router, Used to work, now stopped working. Need help

Well, basically this is how it was working. My router has been working fine for quiet some time, i have an SRX200. My father got a new computer, an hp, and there were some troubles having it connect. Every once and a while, here and there we had to restart it to re-connect, just reconnecting it was not helping, restarting the whole computer fixed it. Now its to the point to where if you close the laptop it disconnects, and NOW its to the point where it wont even connect to the network. It will find the network, which i have named myself so i know it is the right one, but when i try and connect it does not work. "taking too long" or "will not connect". Now i am not a huge Techie or anything, but i know my way with computers. If anyone recognizes the "symptoms" of my problem, i could really use it. Also if i disable the security it usually works, but my parents dont want to permanently do that, and i dont blame them. Once again thanks to anyone who can offer some help.

-Matthew