Stepping away prior to punching the screen is a good idea.
When you're ready to resume this 'ordeal' here are my thoughts. Since I do not know your computer specs, they are not in any particular order, so they can be eliminated in any manor you feel like.
1- The machine is overclocked. If it is, load bios defaults.
2- Memory is throwing errors. http://www.memtest.org/ (burn .ISO to CD and boot it)
3- One (or more) of your External drives has errors. You can run CHKDSK X: /F /R on any drive (sub drive letter in place of 'X')
4- Ready boost is enabled and/or your DVD is being utilized by storage software (ie: Nero).
Now, being a believer in the adage that life is too fucking short, I would suggest after eliminating all of the above (and you must eliminate them or you're wasting both our time) that you format your system drive utilizing the Win 7 DVD and proceed with new install of Windows. Let it update, but do not install any other software and do not attach any other storage devices. Note: prior to install, boot into bios and disable all non-use ports: IEEE 1394 interface, Firewire, Com ports, etc.
See what it does....or better yet....what it doesn't do.......