I had to do that when I bought a new PC and had to transfer all files
It was very easy.

Let's say that you have the following folders:
c:\my Music\Radiohead\In Rainbows
c:\my music\Arcade Fire\Neon Bible

and you physically move them to

d:\new music\Radiohead\In Rainbows
d:\new music\Arcade Fire\Neon Bible

All u have to do is
1. Highlite the all of the above Albums in OrangeCD
2. Right click
3. Properties
4. Go to Misc Tab. You should see an exclamation mark on Album Path

5. Click "Change" on album path
6. Select d:\new music

You're Done !!!