Perhaps you could run the winsock LSP fix, found in the Geeks to go download section. This could possibly fix your connection. Also some spyware can mess up your internet connection. I once renamed a file that I knew was a spyware component and my internet would not work. The LSP fix is designed to replace registry keys that may have been damaged or infected.
You can change settings for your router by going RUN, type in 'cmd', type 'ipconfig' in command promt, and then put the IP address for your "default gateway" in your address bar in internet explorer.
However, since your parents could use their wireless connections just fine, your router is not a likely cause. If you decide to change the router settings, be sure to know what each specifically does is and always be ready to change it back if it doesn't work. It is probably better to leave those alone. You don't want to take down the internet. I've changed settings and I had to work hard to get them back because I couldn't reach my router through my computer..