i don't want to have to go thru this for every clip on the wd drive!! it also seems to be happening with sound files and jpegs.
1 -- I am suspecting that the solution (or the simplest solution) may be to permanently assign that wd external drive the Windows drive letter which the PE 4 Organizer expects (in other words the drive letter assigned at the time the file was entered in to the Premiere Elements Organizer.) Hopefully all files on the same external hard drive expect the same drive letter - which appears to be J.
Why? My experience with another thread that had similar problems was that in Premiere Elements 7, the Premiere Elements Organize panel could not adjust for a change in external drive letter. (This is despite the fact that the Photoshop Elements 7 Organizer can adjust.) I don't have a PE 4 installation to verify that it is the same but in this case I find it unlikely that PE 4 can adjust when PE 7 could not.)
2 -- What version of Photoshop Elements do you have installed ?
This maybe (but only maybe) might offer an alternative. However option 1 above may still be the best if there is no obstacle to your assigning the same drive letter as before your system was reloaded.