SSMS on Windows XP cannot see SQL Server on Windows 7

See more:

SQL-Server

I'm running MS SQL various versions on 2 different machines. And also running different versions of SSMS.

The XP machine is running SP3 fully updated and is 32 bit. The W7 box is fully updated and is running 64 bit ultimate. The SQL servers installed on the W7 box are all x86.

So for example, I have SQL Express 2008 R2 installed on my W7 box. It's configured to allow remote connections. I also have SQL Express 2005 installed on my W7 box. I'm running SSMS 2008 on my XP box. I also opened up a Firewall rule on the W7 box for the port I'm using. TCP/IP is enabled on the sql server. But when I browse for servers in SSMS on the XP box it doesn't see anything in the W7 box. SQL Server Browser Service is running on both machines. Any ideas? I'm at a loss here.