Is there a search index-like feature for Windows?
Something that indexes your files so that you can search though them quickly later.
I like 'Everything'. http://www.voidtools.com/
Very quick, very low on resources!
If you want something that is a lot faster and less resource heavy (though can't index file content), then Locate32 is a great alternative, it is a GUI pseudo-port of the unix locate command (comes in 32 and 64bit versions, is actively developed and is very small and portable):
Windows Desktop Search, at least before version 4 in my testing was very poor performance-wise compared to Google Desktop Search. As I understand it, Microsoft have improved performance in the latest version.
 You can however in the advanced search options, find text within a set of files, but this doesn't use a pre-indexed database...
I really like regain for Windows. It's German, but it is really good. I like it, because it indices all files you want and you can develop own filters, etc.
One problem exist: The priority of the indexing process is setup to
Normal so it disturbs you. I contacted the developer, but there's no reaction yet.
Cathy search utility.
Searching cataloged local hard drive and/or offline filesystems (network shares, CD/DVDs) is almost instant. The memory footprint tiny and the exe itself is under 48K.
Main download: http://www.mtg.sk/rva/Cathy.zip . Because updating the indexes or "catalogs" is manual (which turns out to be a nice feature performance-/portability-/versioning-wise), there's a companion command-line version to script/schedule updating the index http://www.mtg.sk/rva/CathyCmd.zip
neoSearch is a desktop search program that can index your entire system in less than a minute.