Indexing services is a small little program that uses large amounts of RAM and can often make a computer endlessly loud and noisy. This system process indexes and updates lists of all the files that are on your computer. It does this so that when you do a search for something on your computer, it will search faster by scanning the index lists. If you don't search your computer often, or even if you do search often, this system service is completley unnessesary.

Go to Start
Click Settings
Click Control Panel
Double-click Add/Remove Programs
Click the Add/Remove Window Components
Uncheck the Indexing services
Click Next
That's it, you have now uninstalled the Indexing service, you system will not have more RAM and be more responsive.