To force searh indexing to run at a higher priority, install this gadget and hit the "fast forward" button. Windows Live Gallery
Note that it may have some trouble restarting the service, but eventually worked (for me).
I rely a lot on search, so having an up-to-date index is important. I recently moved ~100GB of files to the hard drive, and rather than wait 10 years for indexing, wanted to force it. Built-in Windosw 7 search doesn't allow you to force indexing by giving it a higher CPU priority, but the gadget does. I don't see an easy way to elevate the service otherwise...
And if all else fails there's always Google Desktop