Reasons why you cannot enable the wireless adapter on your computer.
- If you installed the correct wireless card driver, try to enable or start automatically the wireless card service. Go to Control Panel -> Administrative Tools -> Services -> WLAN Autoconfig. Restart the service and try to enable again your wireless network card if can see wireless network available. If still not working. Try to see in your BIOS settings if wireless lan is not configured correctly.
If none of the above solve or fix your problem. Maybe your wireless card adapter has a hardware issue if still you cannot enable it.