What are you using the judge that the corruption isn't in the original CR2 files?
What is likely happening, and a screenshot would help understand more, is that the raw data is corrupted in the CR2 files but the camera-embedded JPG near the beginning of each CR2 file is ok, and whatever software you're using to view the CR2 files outside of LR is only looking at the embedded JPG not decoding the actual raw data. More detailed information would help determine if this is the situation.
Another possibility is that the lines of corruption are not in the raw data but only in the display of the files on the computer, and there is some failing hardware or software component on the computer causing the issue.
If the raw data is corrupted, usually a rectangular area starting at a certain position of the image has odd colors from there to the end, whereas if there is a hardware or driver failure, then only pixel-thin lines of various colors are sprinkled here and there on the image.
I have opened the CR2 files in Camera Raw and they look fine. It's Lightroom that seems to be the issue. I've already downloaded the Lightroom software again and trashed the old version which did not help.
Please make sure that you have selected the latest process version in Camera Calibration in the Develop module of Lightroom.
If it is already selected, change it to 2003.
Restart Lightroom to check if this helps.
If you are still facing any issue, please create a new catalog and import the images to check for the issue.
Let me know if it helps.
Can you upload a sample CR2 that has the issue? I'd like to test in a newer version of LR and see if it still shows the problem. To share a raw file upload to www.dropbox.com and post a public share link, here. You can remove it once we're done and it'll be gone from Dropbox.
This is caused by a hardware malfunction somewhere, which causes the photo to become corrupted.
The problem could be camera card, card reader or USB cable/USB port, hard disk or memory. You need to try transferring the photo to your hard disk again using different hardware, and if possible, using an entirely different computer.
The fact that other programs show the photo properly is because they initially show the JPG preview embedded in the file, and these tend to be uncorrupted even when the RAW is corrupted. So the fact that other programs show the photo properly is not relevant information in this situation.