Spotlight Weirdness

I'm having a problem with Spotlight, and was wondering if anyone who reads this has had a similar problem.

I've just had a clean install on my laptop, and when I do a Spotlight search I get this:

Note that the problem isn't that the search query isn't included in the index, or that the indexing process isn't complete yet, it's that the index isn't even being interrogated. Nothing ever appears below the search request box.

I've tried removing com.apple.spotlight from my Preferences folder, and also tried adding my hard drive to the Privacy section of Spotlight Preferences before adding it again (to force a re-index), but it makes no difference. Tried Google, but there's a similar problem which takes up the first few pages of the results, so I can't find a solution.

Help?!