Unable to connect to ANY wireless network

Computer Type: PC/Desktop
System Manufacturer/Model Number: Custom
OS: Win 7 HP 64bit w/SP1
CPU: AMD Athlon 64 X2 5200+
Motherboard: Gigabyte Technology Co., Ltd. GA-MA770-UD3 (Socket M2)
Memory: 6.0GB Dual-Channel DDR2 @ 387MHz (5-5-5-18)
Graphics Card: Acer AL1906 @ 1280x1024 512MB GeForce 9500 GT (XFX Pine Grou
Sound Card: Realtek High Definition Audio
Monitor(s) Displays: Acer Generic PnP Monitor
Keyboard: Logitech HID-Compliant Keyboard
Mouse: PS/2 Compatible Mouse
Hard Drives: Crucial 128 gig M4 SSD Seagate Backup 5T Seagate GoFlex 2T WDC WD1600JS-00NCB1 USB 1500 Gig Seagate Backup 3T
Internet Speed: Cable broadband (up to 50Mbps)
Other Info: Nightly runs of Super AntiSpyware, CCleaner and Malware Anti-Malware and System Restore.

Computer Type: PC/Desktop
System Manufacturer/Model Number: HP Pavilion p6565uk
OS: Windows 7 Home Premium 64bit
CPU: AMD Phenom II X6 1035T @2.6GHz (hexacore) (=15.6GHz)
Motherboard: FOXCONN (2AA9)
Memory: 6GB DDR3-1333 (running at 1066)
Graphics Card: NVIDIA/MSI GeForce GTX 770 (2GB)
Sound Card: Realtek HD Audio (with 5.1 surround sound always on)
Monitor(s) Displays: HP 2311x (secondary-workspace), Sharp LL-T1620-H (primary)
Screen Resolution: 1924x1080
Keyboard: Microsoft Wireless Keyboard 2000+ HP Media Centre Remote
Mouse: Microsoft Wireless Mouse 2000
PSU: XCase Dolphin, 700W
Case: Stock HP one that came with it, mid-size ATX
Cooling: Stock fans, they're fairly quiet.
Hard Drives: 480GB Crucial M500 SSD 1TB internal WD Caviar Black 3TB Seagate Barracude 7200rpm (for media storage) 4TB Seagate Desktop drive (mirrored backup) 2TB Apple AirPort Time Capsule 1TB Seagate FreeAgent Desk 500GB Seagate External Desktop Drive
Internet Speed: 20 Mbps down, 50 Mbps up
Browser: Chrome Beta
Antivirus: MSE
Other Info: Also: - 13" Apple MacBook Air, 2013, i7 @ 1.7GHz, 8GB DDR3, 256GB SSD - HP Deskjet 3050A - Two HP ZV5000 laptops (the better of the two recently broke) - A Compaq Evo D310 (has 2GB RAM and a 2.53GHz P4 but is curiously extremely slow) - A desk fan - this weather is warm ;) - A fair few retro consoles - Too many cables behind the desk, probably a fire hazard.