Internet connection problems with MN500

Hello,
I have a desktop and a laptop, both running XP Home, and a
cable internet connection. I'm using the MN500 and have
had constant problems with surfing being slow and the
internet connection being intermitent. I have tried and
tried to troubleshoot and have been unable to determine
what is wrong. I did do a ping.exe in one of my
troubleshooting attempts and it seemed that everything
pinged fine except for when I pinged my default gateway,
it was running slower. But I don't know what that tells
me and where else I should be looking for a problem.
Could anyone please assist?

Thank you in advance,
Jennifer