my windows 7 and server 2008 r2 can not access computers in different sub networks. all my computers are in the same work domain and all the xp machines can see and access each other but when trying to access a win 7 machine it say windows cant access \\computername.

The issue may be caused by firewall since the firewall rules may configured based on subnets.Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

1. To access different subnet you need correctly specify the routing information. Analysis of ROUTE PRINT will tell you, if you can reach specified subnet. 2. By temporarily disabling the PC firewall you will avoid blocking packets 3. Network discovery is enabled 4. For file tranfer you need to settle one version of SMB, namely the 1.0.( & Play with autotuning.) Regards Milos