Well, they both fail with the recent shots, but only LR fails with the older ones. I did try reseating the memory as suggested in another post, but of course I can't say for sure if this is the problem or not. The recent raw files are corrupt, so this must be due to hardware (computer, card or camera), but as for the older ones, not so sure.......
1. It's not RAM, CPU, monitor profile, or Lightroom. Do you have any other issues with your computer that would indicate any of these things when running any other programs? If you even suspected RAM or CPU a simple diagnostic would extinguish that line of thought..
2. You downloaded these from memory cards, through a reader, through a port, but failed to mention any of the variables which could actually corrupt your data. Such as what type of card reader, what port, through which type of interface, the destination medium.
3. You also failed to mention if the files are intact on the original card (can you view them on the camera) which would only indicate the embedded jpegs are okay, but that's a start. If you still have the original files on the original card did you try downloading them to another computer, through another port, via another reader?
4. Your chances of recovering the files from the destination medium you're reading these examples from is nil. But you might be able to recover from an intact card, or even a re-formatted card (never, ever, reformat or erase a card until you've verified your files on two different destination mediums) using recovery software. If you can do this, try another computer, another reader, whatever other variables you can think of.
5. Before posting on a forum asking for help, now two forums, do the basics yourself. (discussed above)