This was such an odd problem, I wanted to share it in case any of you encountered the same thing.

Any move toward being 'paperless' or using less paper means PDF files. Here at IT Xpress, we store invoices, receipts, and more in PDF files. With the new search tools in Vista and Windows 7, we figured we could easily search a folder looking for an receipt that had a certain product. Apparently not. If you use a '64-bit' version of Windows, Adobe has not released a filter that allows you to search PDF documents. Annoying! But thankfully it can be fixed…

1) See if you are running a 64-bit version of Windows. Click the Start Menu icon and right click on 'Computer'. Select Properties and look at the 'System Type'. If it's 32 Bit – you can already search PDF. If it's 64 Bit – you can't and need to do this.
2) Go here and download the necessary search filter:
3) Unzip the file and double click the installer. Accept all defaults until it's finished.
4) In the control panel, (Start -> Control Panel) click on Index Options. Click the Advanced button, allow it to run, and click 'Rebuild'. This will rebuild your indexes and include PDF files in the search database.
5) Wait. A Loooong Time. Indexing is slow to avoid dragging your system to a crawl, so it may take hours or even days to reindex all your files. Once that is done, you should be able to search inside PDF files!