It needs a driver. Can you cable to your router to get a connection? If so, click on that yellow marked entry and then on Update Driver. If your settings allow, the system will seek a driver from the Net. If that doesn't happen or you can't connect directly, us the computer you're posting from to find the right one and transfer it using a memory stick or flash drive. For that, you need the precise details of the wireless card so back to Device Manager, click it up again and click the Details tab. Note down the first four characters in the PCI and DEV sections then input those in the relevant boxes at this site http://www.pcidatabase.com then note down the name of the manufacturer and any model details you see.
I just instaled a router to connect my wi-fi laptop and cannot find the available networks option and when I checked device mgr, it reads two network adaptors with on showing a yellow exclamation point and am unable to connect my laptop.
With luck, there will be a hyperlink straight to the driver download but it's best only to trust the maker's own website and not some of the riskier sites which wan't to scan your system and sell you something you probably don't need and which won't work properly anyway.