Everything posted is true. There are other issues to throw in the mix. If the other suggestions still haven't solved the problem, I would also try these angles- 1) update your wireless NIC driver. If it's integrated update your BIOS. I've had similar problems clear up with a driver update. 2) update your router firmware Not sure if you are doing any sort of authentication, but experiment to see if this is the cause (I've had numerous issues with soho routers and WPA). If so, hopefully the firmware update will help. Check to see if any other wireless networks in your area.