I would only do a temp uninstall of Mcafee
for sure only as a test. Because you should be able to ping via name. If you can't then this is a DNS problem. Please go to the command prompt on xp & 7 ipconfig /all Enter
Are both machines showing the same DNS server eg 192.168.2.54 the dns server showing here should be the same ip as your router. If it is please power down the router for 30 seconds repower and test again for connection.
I have one more thing to try before removing Mcafee. Checking wins and netbios can help.
When you do ipconfig /all it should show netbios over tcpip enabled. If not,
Go to Network and sharing center>change adapter settings>Right click on adapter>properties>
Click on Internet protocol Version 4 (tcp/ipv4) click on properties>click on advanced>dns>
The following 3 should be checked
Append primary and connection specific dns suffxes.
append parent suffxes of the primary dns suffix
Register this connections address in dns.
Click on wins tab
Enable lmhosts lookup
on the Netbios settings the usual setting is default. please change to enable netbios over tcpip - Do the same on xp.
I have been slowed by my isp so internet running sloooooooooow. So no screen shots for now please.
I do have a question. Why would Mcafee not let the windows 7 and the xp communicate?
Strange I know but it happens. May I have model number of router I know its an N but exact model please. Can all machines access the internet. Is the xp home wireless or hardwired.
With the xp machine not showing in the network map this is not an issue. However if you want to put it in the map here is a link on how to do it(The article is for vista but will be the same for win 7)Click on me
It could help to show were the break is.