Two other good things to do once you reset the router with a new password, and a new WEP Key, is to configure it to utilize the MAC address filter if so equipped. You'll want to configure that as "Allow Only these". You'll have to collect all PC and device MAC addresses that connect to your network, but it is a good security measure. The other thing to do once your security is configured is to turn the Network ID broadcast off, if they can't see the SSID they have a much harder time getting in.