No the computername must be different but the Workgroup must be the same.
Make sure you give the both computers a different name but put them in the same workgroup.
Then go to my netwok places.
Then click on "View workgroup computers"
Normaly then you would see both computers (they must be turned on!!)
If the computer is protected with a password then you will have to give the username ans password.
Did you change the firwall because I think that is the problem with the newest computer or do you have an other firwall?
If so plz tell me with so I can provide more info.
Or it can just be because the newest computer doesn't share anything.
Sorry that it took so long to answer.
Oh PLZ let me know how it turned out.
Jonas