Window 7 won't detect wireless network

I purchased a new NIC.
1. Uninstalled old driver for the original/old NIC that is to be replaced.
2. Shutdown PC. Installed new NIC. Power on (new NIC: TrendNet TEW-726EC PCIe - 300 Mbps Dual Band Wireless N).
3. Disabled ZoneAlarm Firewall and Microsoft Security Essentials, installed new NIC driver.
4. NIC is not detecting existing network or anyone else’s (i.e. neighbors).
5. NIC is enabled- Confirmed. Rebooted PC and router, etc.
6. New NIC IS visible in Windows 7 Device Manager and it’s active/enabled. NIC is not detecting existing network.Disabled then re-enabled NIC. NIC is not detecting existing network.
7. **By not detecting the existing network, it won’t even see it, and not even give me the option to enter my key join.
8. Ipconfig /release, ipconfig /renew, FlushDNS. NIC is not detecting existing network.
9. Just for kicks, I tried Windows 7/Microsoft troubleshooting and went through all steps (what a joke).
10. New NIC does not have static IP, DNS set, etc.
11. Reboot. Tired different driver versions. NIC is still not detecting existing network.
12. Checked Router (about six months old wireless, D-Link, DIR-655 Xtreme N), broadcasting SSID, ALL seven of my other devices (laptops, iPhones, iPad, BlueRay players) all are on the network and detect router.
13. Router accepts a/b/g/n/ac. 802.11 - Mixed Mode.
14. DHCP enabled on router. Fifty IP addresses are in the DHCP reserve.
15. WPA2 on router.
16. Transmission Rate: Automatic
17. NAT disabled.
18. MAC address filtering is on, but remember it’s not even detecting the router/network. So, I never get to add the MAC address of the new NIC anyway. Tried to add the MAC address of one of the NICs, still nothing.
19. Set to auto Channel Scan. i.e. scans all channels (not static).
20. WPS not set up on router.
21. Wireless access is “scheduled” as ALWAYS.
22. Removed my iPhone from my network and then added it and it was detected automatically.
23. Tried a second NEW NIC…. TrendNet TL-WN951N with same results as above. Called TrendNet tech support and they made me go through all the same steps I tried with same results. TrendNet tech support replaced the second NIC, same problem again.
24. Tried a different NIC…. ASUS PCE-AC56 802.11ac, Dual-band Wireless-AC1300 with the same results as above. Old drivers are first uninstalled properly and new drivers installed, reboots, etc. Nothing.
25. All new NICs can’t get an IP address or detect my network, but are all seen in Device Manager.
26. The NICs, I am convinced, are not the problem.
27. Re-added old/original NIC and it’s detected when I login. I can surf, logon to my wireless router, etc. *******HOWEVER, after about an hour or so ( I never timed it), my old/original NIC “disappears” and I have the same problem as I have with the new NICs (see above). Then I have to do a restore from previous day or previous restore point and then the original NIC connects and all is fine just slow since the NIC is old.
28. Windows 7 is up to date with patches, updates, etc.
29. ALL NICs are experiencing the same problem. The only thing that is saving me is that I can restore to a point where the old/original NIC was working and I can go from there.
30. Please help.