Vista Error with Network Security settings

Recently I had to scrap my old computer, it just plain comped out on me if you get my drift. I picked up a $600 dollar pos computer from walmart just because i wanted to be netborn again (btw im on a laptop NOT MINE right now hahaha)

well everything was fine and dandy, turns out it had vista, yay, im just so estatic (heavy sarcasm) well at the time my brother also had a computer in his room (xp) he didnt get crud for internet connection, it was supremely slow, same with me. So he went out and bought the Linksys N Ultra Range router network thingy I dunno what it is, dad set it up as his computer is master computer, well my brother could connect just fine but vista always poped up saying the security settings for my computer dont match the networks settings, well i went through holy hell getting it set up, my settings were wep aes (whatever that is) plus the key to let me use the network, well it would connect then disconnect telling me the security settings did not match, i tried tkip but that didnt work either, then i tweaked something (i cant remember what) and everything was fine and dandy, although my brothers computer later died, i assume to old age. I left for the summer to my sisters, came home, found that my brother and his girlfriend had ammased a large ammount of crap on my computer and i could NOT use system restore, the bugs in it had destroyed all my firewalls ect. So I did what option i had left, i reinstalled vista and partitioned my harddrive so that it was "a clean slate" so to speak. Well ive installed everything had linksys put back on the computer, everything was fine and dandy but now its started with "security settings do not match. and it absolutely will not let me online at all no matter what i do even though my security settings DO match...... D: is it just vista? I have no idea what to do and i want back online. I thought maybe it was because it had wep on it but it doesnt affect my dad or my brothers gf (though they have xp) any advice is greatly appriciated.