It sounds like perhaps you have been hijacked or have a virus or some sort of spyware/adware. Using a wireless router shouldn't mean that you'll be bombarded with popups, but be sure you have your firewall running and security enabled on the router, just to be safe.
That said, try running a virus scan with whatever anti-virus you have installed. If you don't have anything, use TrendMicro's HouseCall (http://housecall.trendmicro.com/
). That I believe also will, or will give the option to, check for adware/spyware. If it doesn't, or if it doesn't find anything, try downloading a program like Spybot Search & Destroy (a personal favorite). You can download it here
. Run a scan with Spybot and delete anything that it finds. Make sure you've set up Backups in the Spybot options first, and take a system screen shot via System Restore before you do anything.
If you need additional help, please let me know. Hopefully this helps though!