How To Fix Ip Address Conflict? And This?

I’ve a wireless router set up with my Windows XP PC. It connects fine with the PC but other devices cant detect the wifi, it worked yesterday and I think there maybe something set wrong to the wireless network. I’ve tried connecting to this wifi with iphone and laptop none of them even detect the wifi so any solution?I’ve set the security with no password required. The problem is I don’t even know the name of the SSID I don’t see it on the tool/task bar so I searched in the network connection and found only one connection that says Local Area Connection, I restored the setting in that and still doesnt work I don’t know whats wrong but lately it says there’s an ip address conflict so maybe that had something to do with it. Mind u Im really a beginner when it comes to computer networking so keep it really simple if possible