There is nothing to uninstall, but you may need to access the router pages to set up your isp's details - the router should have the number to input into your browser. It will be something like 192.168... I have never come across a 'guest' account before - all the routers I've seen have had just one wireless password. WEP is not considered good security anymore - WPA2 is better, and the router will have that I'm sure.
What is ransomware and how do I protect my PC from WannaCry?