text: 1 Answer
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  One suggestion, is if you have access to say... a Linux liveCD or perhaps a Hiren's CD with an "Mini" OS on it to boot from and see how that works. If all is good I would lean towards some kind of corruption of your system files AND potentially that USB Drive as well (where/when did you make it? Any possibility at all it's not pristine to use? You can also make a Hiren's bootable USB Key so I might try one of those... or perhaps also a Linux one http://www.backtrack-linux.org/tutorials/usb-live-install/ is one that I like). I still would go with a CD first then try a USB just for giggles to see how they both react. Another choice is to try and boot a Windows installation CD/DVD. You don't have to proceed obviously but see if it can detect your existing installation and if you have a backup... you could even give Windows Repair a shot. I tend to have some pretty good luck with it at the Office.
  
  Gosh another thought I forgot was to try Windows Safe Command Prompt. I have had luck with that a few times when both normal and safe mode failed and I wanted to a system file check (sfc /scannow). If it's corruption of a DLL file or a SYS file, this has a good shot of fixing it.
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  OG Chuck LowDec 10 '11 at 21:42