Hi, I have 4 computers, Cable Modem and Dlink wireless router. I have connected Modem to Dlink Wan port. First computer to Wired lan port, Rest of the 3 computers are connected with wireless adapter. I want to use all the computer independently to connect internet. I have setup router as gateway to automatically assign lan address. Internet works except filesharing between computers only works once and while most of the time it gives me a error of network path not found. I can ping all the computers with IP but cannot ping by name. I am using workgroup connections. I have setup all the computers using option 2 as using gateway(dlink router). What am I doing wrong?

Have you called D-Link tech support? They have 24/7 toll free support that is very good from my experience. I would call them.

I did They will only help with Router config. Since all computers show up in mshome, They say it has to do with windows firewall. But If I renew my connection it works for a while than it says Network path not found.

So junk the windows firewall and use Zone alarm instead.

So junk the windows firewall and use Zone alarm instead.
I just through the same issue on my wireless setup, wireless devices had access to internet but could not see shares on other computers, and ZoneAlarm was the cause. Once I shut it down my shares appeared.

I just bought a wireless router and had the same problem. Turning off windows firewall on wireless connection (in Network Connections) solved the shares problem.

Could turning off firewall on wireless adapter, make my computers more unsecured to internet?

The purpose of firewall is to protect your system from external attacks. Every broadband connected system needs some firewall protection.