Help with virus/spyware?

Well when I got this computer, it came with a 90 day trial of Norton Internet Security+Anti-Virus, and after it expired I got Norton 360 All-In-One. I had to uninstall the old Norton to install the new one, so I did. Then when i turned on my computer at the task tray (or whatever it's called, the icons at the bottom right.) There was a flashing red circle w/ a X in the middle and it said "System Alert". My background was overlapped by a big red toxic sign and under that "YOUR PRIVACY IS IN DANGER!". A lot of pop-ups kept coming up saying "System Alert" "Worm was detected on your computer, click yes to delete this worm now.", "Windows Security Alert" "Windows has detected an Internet attack attempt... Somebody's trying to infect your PC with spyware or harmful viruses. Run full system scan now to protect your PC from Internet attacks, hijacking attempts and spyware! Click here to download spyware remover for total protection.", and when I open up Internet Explorer, the home page is an ad telling me to buy a spyware remover. Even when I change the homepage, it changes back whenever I open Internet Explorer. I installed Norton 360 All-In-One and ran virus scans and things, but they didn't detect anything. Should I get a different anti-virus program? Thanks for the help =]

Help with virus/spyware?spyware removal