What's the firmware version? Upgrade Archer C2_V1_141117. http://www.tp-link.com/en/support/download/?model=Archer+C2&version=V1#tbl_j Before you restart the router, both wired and wireless...

If so, remotely, are you using Putty as well with WAN port and port 22? I noticed that you opened two ports for the host. What does 1025 work for? Disable anti-virus and windows firewall to test.

To turn off Hardware NAT won't cause it except that you disable NAT as well. Are you connecting to 2.4GHz only or dual band? How many wireless clients there? The router is on all the time or you...

Chris, report it here directly. You'd better provide a topology which will be more clear than the description.. http://ticket.tp-link.com/index.php?/Tickets/Submit

MTU VLAN should be able to work in the way you like. Clients connected to SG108E cannot communicate with each other but they can talk with netgear router to access internet.

It is not in compatibility list but you may try this beta firwmare which I get from TP-LINK support....