Only other thing I can suggest is a factory reset of the router.
I had an issue with a Netgear some time ago where it wouldn't allow connection to secure sites such as my bank,, credit card company, Outlook Web Access at work.
Tried switching off the router for a couple of hours, the ISP I was with at the time even checked my account on their network to see if anything odd was happening but to no avail.
I was about to ditch the router but decided to try a factory reset which cleared whatever issue had occurred within the firmware of the router.
Make sure you have your ISP's userID and password to hand.
