Router Is Connected But I Sometimes Cannot Use The Internet

I have this Netgear (WGR614) wireless router and I’m having this problem with it. It’s connected to my laptop fine and the signal strenth is usually “Very Good” or sometimes even “Excellent.” However, my laptop will often say that it is connected but the internet won’t work. Do I have something hooked up incorrectly? But there are also times when the internet is working just fine so that is why this is so confusing to me.
My OS is XP.