|Ok, you have the most recent firmware installed and nothing has changed on your end. The next step I would take would be reset the router to factory defaults and reconfigure it and test. If it works fine, you're good to go. If it doesn't work properly then you need to contact the manufacturer's support line and have them run you through some troubleshooting with them.|
Since the internet works perfectly when you connect your PC directly to the modem, this indicates that neither your ISP nor your PC/laptop is the problem so that leaves only the router.
It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.