If you want to use the Windows search by itself - for instance to look for .obj files when Poser can't find them, you have to include the obj extension explicitly to the Windows search indexer. The default will not include them in the index (although you can find them with a complete search, which is much slower)

I think the Windows search is really useful since you can invoke it directly from the open/locate window - just do a control-c (copy) and paste it in the right top search box. Given all the broken references of texture and obj files over time it is a real time saver.