Wired to wireless connection problem

I have an old/updated desktop running windows 98. I have the cable modem hooked to it and a wireless router. The internet connection light on the router goes off while the cable modem is on. If I turn off the cable modem or put the modem on standby, the router internet connection light comes on. In any event, my laptop sees the wireless connection; says I’m connected but won’t bring me to the internet… Any help will do.