Desktop can't find wireless connections, but other devices can?

I have been currently trying to connect to the internet using my desktop. I'm able to connect using my iphone, pc laptop, and mac, but not my desktop. My desktop is running on Windows 7 ultimate. I purchased this desktop a couple years ago as a vista, and upgraded it to a 7.It's model is HP Pavilion?

I have tried searching up several solutions, and tried entering different command prompts and unplugging the modem and plugging it in again.

When I look at the Network & Sharing Centre, it says that the Network Unidentified on a public network. The icon shows a little yellow triangle with an exclamation point in the centre.

When I view the status of the local Area Connection, (which is an Intel(R) 82566DC Gigabit Network Connection), it says the IPv4 and the IPV6 connectivity has "No Network access".

When I run a troubleshoot, the problems found is "Local Area Connection doesn't have a valid IP configuration - Not Fixed"

Can anyone help out with this please? It's been like this for about 24 hours now.

First that yellow triangle with the exclamation sign means there's a missing driver. You need to update that driver else it won't work. Secondly, just uninstall the modem software on your desktop and reinstall it. Go to options in the user interface that opens after the software is installed and select profile. Setup the profile for the network you use in the modem. Untick 'use IP address.

The network should be set to home network. The wired network adapter (Control PanelNULLetwork and InternetNULLetwork Connections), right click on Local Area Connection, select properties, scroll down to TCP/IP v4, click properties, should have "obtain IP adderss automatically" and "obtain DNS address automatically" checked. Your modem/router should be set to DHCP, ie to hand out IP addresses to connected computers.