Here's how you can get Windows Search to index a "removable" drive in 7:
- Create a new folder on one of your hard drives. (i.e.: "C:\Code")
- Go into the Disk Management, right-click the removable drive and pick "Change Drive Letter and Paths".
- Click [Add] and select "Mount in the following empty NTFS folder".
- Choose the folder you made earlier ("C:\Code").
- Now if you go to C:\Code it should actually be the USB drive.
- Via Explorer, add a new Library and add the C:\Code folder to it.
The indexing should now index that for you.
If you want to index inside the files you'll have to go enable that (for that folder) in the Windows "Indexing Options".
You can probably use the Indexing Options to avoid making a Library.
Note: While you are playing with the Indexing Options, don't be surprised by long pauses if you already have a large Windows Search index.
Your mileage may vary once you start unplugging and plugging the drive. :)