Windows 7: In real trouble - Stuck in mid-install

System Manufacturer/Model Number Self-Built in July 2009
OS Windows 7 Ultimate x64
CPU Intel Q9550 2.83Ghz OC'd to 3.40Ghz
Motherboard Gigabyte GA-EP45-UD3R rev. 1.1, F12 BIOS
Memory 8GB G.Skill PI DDR2-800, 4-4-4-12 timings
Graphics Card EVGA 1280MB Nvidia GeForce GTX570
Sound Card Realtek ALC899A 8 channel onboard audio
Monitor(s) Displays 23" Acer x233H
Screen Resolution 1920x1080

Keyboard ABS M1 Mechanical
Mouse Logitech G9 Laser Mouse
PSU Corsair 620HX modular
Case Antec P182
Cooling stock
Hard Drives Intel X25-M 80GB Gen 2 SSD Western Digital 1TB Caviar Black, 32MB cache. WD1001FALS
Internet Speed 15/2 cable modem
Other Info Windows and Linux enthusiast. Logitech G35 Headset.

System Manufacturer/Model Number HP
OS Windows Vista
CPU Intel Pentium

System Manufacturer/Model Number Gateway, Toshiba Laptop, and Home Brew
OS Windows 7 x64 HP, Windows 7 HP, Windows 7 Ult
CPU Intel I3, Cerelon, Pentium 4 @ 3Ghz
Motherboard Intel, Intel, Asus
Memory 8G, 3G, 3G
Graphics Card On-board Intel, On-board nVidia, nVIDIA card
Sound Card on-board, on-board, SoundBlaster
Monitor(s) Displays Hannspree HF237, Toshiba, SyncMaster 931B
Screen Resolution default (all)

Keyboard standard wired (all)
Mouse standard wired (all)
PSU 300w, unk, 650w
Case black, black, grey
Cooling air (all)
Hard Drives 1T internal, 320G internal, 160G internal, 1T networked
Internet Speed 6M down, 768K up
Other Info Home LAN through Linksys hub to 4 port and wireless switch/router. Networked HP 2600n. Wife's computer running Windows 7, and spare laptop running Ubuntu "Karmic Kola" (9.10).