Google Desktop – (Note: Google Desktop is no longer available). Let's start with a solution to finding files FAST that will work with all computer systems: Google Desktop at http://desktop.google.com/. As Google explains:
"Google Desktop makes searching your computer as easy as searching the web with Google. It's a desktop search application that provides full text search over your email, files, music, photos, chats, Gmail, web pages that you've viewed, and more. By making your computer searchable, Desktop puts your information easily within your reach and frees you from having to manually organize your files, emails and bookmarks. Google Desktop doesn't just help you search your computer; it also helps you gather new information from the web and stay organized with gadgets and sidebar. Google Gadgets can be placed anywhere on your desktop to show you new email, weather, photos, personalized news, and more. Sidebar is a vertical bar on your desktop that helps you keep your gadgets organized." ~ Google Desktop Website
If you need something, do a search for a word you remember from it and boom, there it is! You really can't beat this and my own experience is good with it. I have to say that the addition of voice to this is a plus, as well!
Bonus: Google Desktop will search emails, too!
Windows 7 - Easy! Just go to the Start menu and start typing a keyword, title, or other search item and a list will pop up as it searches your computer. More information on this can be found at http://windows.microsoft.com/en-US/windows7/products/features/windows-search.
Apple OS - Use Spotlight to find items easily. I'll admit to letting this sit too long unused on my Mac. What a waste of a great tool. Here's information on using it and the Finder with the new Mac OS, Lion: http://www.tuaw.com/2011/04/06/mac-os-x-10-7-lion-features-new-system-information-app/.
The main thing is that we have these great tools that make finding those documents so much easier than what is normally done. One of my goals is to use those tools more efficiently to ensure that I get the most organization possible!