Laura, I'd guess this is not promising for you. TIFF files tend to be large, so I am wondering if you might have closed Photosho and the PC before it had finished saving? Do you remember the pixel size of the original image, and what is the file size in Mb? I am not sure how Photoshop treats TIFF images, depite them owning the file format after buying it from Aldus a few years ago, but it sounds like it was saved as a series of tiles, and the information about the order of those tiles is corrupted. You might be able to Google TIF file recovery program, but it is unlikely you'll get the full file back with all the information saved with it.
If you don't get a better answer, keep a weather out for when Chris Cox is posting, and bump this thread.
That does sound like the file was corrupted when it was written, or by some problem with the disk.
The left/right problem could be solved using the offset filter - but I bet there is also a 1 pixel vertical shift (due to reading the data out of phase).
Did you receive any error messages when the file opened? If there was bad layer data, it should have given you some sort of error.
I can't remem ber the pixel sizw but it was 120cmx70 with a 150dpi. I googled Tif file recovery but found nothing of any use as it has lost its layers.
When I opened the file I received no error messages. It opens as normal except for the no layers & reversed sides.