Encryption Trouble

Hi everyone, I run a wireless network with 5 computers connected (two plugged, 3 wireless) on a netgear router. All three of the wireless devices are running windows XP home. Up until a few minutes ago, I had WPA-PSK encryption enabled.

Recently, my sisters computer died. She had the hard drive replaced and windows reinstalled. When she brought it home, she asked me to set her up on the network. I right clicked the wireless network icon in the system tray and clicked 'view available wireless networks.' Instead of this familiar screen, I saw one that looked like this, which I had never seen before:
http://img218.imageshack.us/img218/3423/connectkf5.gif

Our network showed up in it, but a message appeared stating that the network uses a WEP key (pictured above, greyed out). This is INCORRECT. It does not use a WEP key, it uses a WPA key. When I try to enter the WPA key in the "network key" box, i receive a pop-up box stating that WEP keys must be between (i believe) 8 and 24 characters (my WPA key is 63 characters). So, I grudgingly changed the network's encryption to WEP. This is where problem two begins.

My sister was able to connect flawlessly with the new key. My computer simply when I attempted to connect to the network. My computer was set up to connect to my network automatically at startup (this meant it froze within 20 seconds of startup). The wireless connection manager still erroneously listed the network as WPA and absurdly listed me as connected (I wasn't). So I turned off my wireless card, to prevent my computer from attempting a connect. I went to my list of preffered networks, and deleted my home network, presuming it would now ask for the key at connect. I turned on the wireless card, and attempted to connect again. It froze again.

So, the situation is: my computer will not accept WEP, and my sisters computer will not accept WPA. For right now, my only security is MAC filtering. So

1. Why does her computer no longer accept WPA?
2. Why does my computer not accept WEP?

 

Might be that the new installation uses old drivers, log to the support site of your sister's hardware, and look for updates.

As for WEP.

Manufacturers generate WEP keys in different way. Generate a WEP key in the Router and, copy the first HEX key that the Router generated from a passphrase to the Wireless computers. I.e. use the actual key and Not the passphrase.