WNDR3400v2 not connecting to internet (but works with VPN?)

My router is broadcasting wifi networks, but I'm unable to connect to the internet with it. I've confirmed that I can get online when connected directly to my modem, and even reset the router to factory settings... I still can't get online. The weird thing is that I'm able to get my VPN connection running and connect to the internet that way. I have no idea what's going on, I've tested it on other computers with no VPN set up and can't connect to the internet.

Please help!