Go to your start menu and find the run command window (alternatively press Windows button + r)
type: "services.msc" (without quotation marks) and press enter.
Find "Windows Search" on the list and make sure it is set to "started" and "automatic"
do the same thing with "indexing service", though this might also be found if you right click on your harddrive and press
"properties" - make sure that "Allow files on this drive to have contents indexed in addition to file properties" is enabled.
I don't know ape about Windows 8, but I assume that these commands are the same.
Hope this helps