icey_kitsune,
On 5.0GHz, I'm not sure what are the best channels to use. The higher the channel, the smaller the antenna, the better you should be able to connect.
Go to Drivers & Downloads enter your service tag number, then select your operating system. Under Network, download and install the latest drivers.
Try these tweaks....
Start, control panel, device manager. Click on Network and then right click on your wireless adapter, left click properties, power management. Uncheck the box, allow computer to turn off this device to save power.
Click on advanced. Look and see if this adapter has Antenna Diversity. Some adapters have Antenna Diversity and some don't. If your adapter has Antenna Diversity, change it from Auto to Aux.
Go to the power options, and changed the Wireless Adapter Setting, from Maximum Power Setting to Maximum Performance.
I looked at the manual and it looks like the wireless adapter is under the keyboard. I was going to also suggest to check to see if the antenna wires are on securely.
Rick