Give Tag&Rename a look.
No personal experience with it, though - sorry.
Being a long-time MC user, I've long been in the habit of making sure that anything not ripped with WMP has full tags (including "Album Artist") when I add it.
FYI: In the future (for new music that you add), you can edit MP3 tags in Explorer. If you 'select all' in a folder, you can batch-edit the common tags for all tracks in an album>
Doesn't help you now (not with 45,000 tracks to edit); but, something to keep in mind in the future.
HTH
~Chris
'nearly every day of my life is some kind of computer hell'
Desktop: E7300 on GA-P31, 2GB, HVR-1250, HVR-2250, ATI DCT (internal), HD4650, Win7 Pro x86.
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