I recently changed internet provider and rented a D-Link N 300 Router. On most days everything works well. However on some days the internet connection on my new laptop that has Intel Centrino Wireless-N 130 network adapter get really terrible (usually on Friday and Saturday). At first I thought that the problem was with provider, but now I find out that my old laptop that does not support 802.11n (only 802.11g) has excellent internet connection (at the same time when the new laptop struggles).
How can I troubleshoot what is causing this problem - the laptop network adapter or the router? Is there some setting for network adapter to force using 802.11g?
My laptop is running Windows 7, if that matters.
EDIT: After running inSSIDer I found more than 20 APs and so it seems that Dave's answer is at least pointing in the right direction. Here's a picture of the channels (my AP is CGATES_...). I'm not sure if I'm looking at the right stuff yet, but hopefully I'll be able to help some help from my provider after the weekend or figure out how to configure the router myself.