Windows Search Indexer starts building index after every logon from the very beginning all over again and again and again. Manual index re-built won't help, nor reinstalling the service itself. I have tried every possible setting, except completely disabling the service (that I don't wish to do). I'd be grateful for any ideas, what might be causing this. The problem appeared apparently without no reason, only recent security patches have been applied. Using WinXP SP3, have no spyware, viruses, etc. (I'm sure of this.) No special software. Otherwise search itself works just fine.
Thanks for the answer, I have already found solution that works for me, so for the others who have similar issues:
Disable "Allow Indexing Service to index this file" file attribute for the entire drive, and then re-enable it only where desired (Documents, Pics, etc.).
Manually stop Wsearch service, delete entire All Users\Application Data\Microsoft\Search directory and reboot. All settings will be reverted to their defaults and index rebuilt.