Exclamation points! Everything is in the right place, HELP?

Hi - I know someone here can help me…I have a pretty big library, about 18,000 songs, that I just moved from my PC to my Mac. I moved the DB files to repopulate my library (worked fine), I moved the music files and was sure to put them in the place iTunes defaulted to look for them on my hard drive, everything seems to be pointing to the right place, and yet the exclamation points and "original file cannot be found, would you like to locate it?" And when I click yes, it opens the iTunes Media file (where the music files are!) and I have to click on the artist file and then the music file and click "OK" and the file plays. I've done this with a handful individually, but I can't do it for 18,000 files one by one…can anyone help me? I've Googled, been here on Apple, been on YouTube, and I still can't figure out why it's not working.

Any advice you can give me is GREATLY appreciated! I need my library for my job, so it's pretty important for me to get this thing to cooperate! Thanks in advance!!

~E