I will assume that you are simply trying to attach a PC using the adapters and not set up a remote AP, as that has some steps that could be the issue.
I would personally try troubleshooting them, and if that fails just exchange them. Most are simply plug and play.
Insure that both are in outlets directly (not on powerstrips), insure that the cable from the router LAN port to the first adapter and the cable from the second adapter to the PC are both working by testing them both with something else, like attaching your PC directly to the router LAN port, and take a look in your router when everything is attached and all lights on and PC powered up to see if the PC is getting an IP address in the router DHCP assignment table. You can...