I had a lightroom previously installed on my computer and it worked fine but when I purchased Lightroom 4 and upgraded recently. Now I am unalb to view the thumbnail previews of my photos and if I do blindly import my photos I cannot see them in the grid or in the develop mode. I am using two monitors and when I have the grid open on my second monitor I can see the pictures but when I move the develop screen to that monitor Lightroom crashes almost instantly.
This is a screen shot of what I see when importing pictures on my main monitor. My computer is only 6 months old and built with all brand new hardware except for a video card which is only a year and a half old.
Since your images basically don't show anywhere in LR, I figure your monitor's colour profile is corrupt. Try changing it to some flavour of sRGB and see if that helps. If it does, it's just a stopgap measure until you can calibrate your screen properly using a Spyder or EyeOne or something similar.
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