CISCO ME 3400 LAN configuration

Hey
I faced these problem before many times , the problem is contained in the same PCs because the vision of operationg system is not well .
So you should format the OS and reinstall it again .
Am sure the problem well gone .

Check out the Cisco Docs on the ME 3400 Metro Ethernet Switches, especially the section on types of Private Vlans and Private Vlan Ports, this looks like the problem you are looking at.
This maybe the wrong device for your infrastructure.

http://www.cisco.com/en/US/docs/switches/metro/me3400/software/release/12.2_37_se/configuration/guide/swpvlan.html#wp1067012

If you are using Windows 7 you may have to tell the Win7 firewall to allow ICMP packets. Go here:

http://lmgtfy.com/?q=How+to+enable+ping+response+in+windows+7

Win7, by default, does not allow ICMP to pass through its firewall. Hopefully this helps you. :-)

-=K=-

We need a little more info. what is your switch and router configs ?
but until we see more info you may want to see that the switch ports have been assigned the correct VLAN number, and that the PC's firewalls have been configured to respond to pings.

one way to check the firewalls of the PC's is to plug them into an unmanaged switch (no VLANS).
you should be able to ping between the PC's on the same sub-net.