No connection with WPA-PSK

I've just lost the ability to use WPA-PSK on my wireless connection today. This seemed to happen after a security update. If I disable security, i can connect to the Netgear router but with WPA-PSK it cannot see the access point. It works fine if i reboot into Windows. I haven't tried using WEP instead as I now have a flat battery. Has anyone else hit this problem? regards Ian