N900 gives Limited or No Connectivity on wireless

I have the N900 using both 2.4 and 5 ghz.  I have a couple of older laptops running XP that only access the 2.4ghz band.  Since I had this router, they have trouble acquiring a network address.  Sometimes they work, sometimes it just keeps searching, or then connects with no internet.  This never happened with the old router.  Any suggestions what to do? 

egruber,

I would recommend ensuring that your router is up to date with the latest firmware, as this may easily resolve the issues you are experiencing. If you have already done so and are still experiencing these issues, in the interest of troubleshooting, you may want to reset the device back to factory default, as this will remove any residual configurations that may be causing conflicts within your network from an update that did not fully reset upon reboot of the unit.

The firmware is the latest.  And I didn’t change much from the defaults.  I did change the channel to channel 1 because I was having issues with my Roku box and that is what they suggested.