internet connectivity issue on laptop

Internet connectivity issues on laptop?
I have a wireless router hooked up to my dell desktop. And I access the
internet sometimes through my toshiba laptop. Lately, there has been pop ups
that say, Dial-up connection. and I always click on cancel then another pop
up would appear saying Web page unavailable while offline. However, my laptop
says its connected to the internet through my network and I have no problems
connecting online through my desktop. Now I cant access the internet on my
laptop without those two pop ups occurring even though I am connected to the
internet on both my laptop and my desktop. Please help me solve this issue!
oh btw, my laptop is running on vista home premium os and desktop is on xp.
thanks!!