Originally Posted by Plankton

I'm guessing, but try this:

Start > Search > (type) index and select "Indexing Options".

Select "Advanced". Under the "Index Settings" tab select "Restore Defaults".

I'm thinking something went cattywompus with your index settings. Other than that, it might have something to do with Page Filing and you're resources are too low. Again, just a blind guess.

Edit: Don't forget to reboot.