Everything search engine is a free software that locates files and folders instantly as you type. It indexes all the files and folders in your hard disk. The speed is phenomenal , much better than windows built in search. I use it everyday to open my files instead of explorer. You just have to remember part of the name, type it and instantly you can locate it.
No more crawling through complex directory structures. You just have to name your files in informative way.It monitors change real-time by using the NTFS USN Change Journal, so any new file gets added instantly to the index. It takes only about 5-20 MB of RAM so no performance hit.
A good review can be found at freewaregenius.com
Download here : voidtools.com