You'll have to define "not working". What isn't it doing? Does it not show up? Is it missing from the menu? Has it lost it's "new car smell"?
I know it's possible to turn off previews from within the printer driver/spooler on some printers. My Epson software will override whatever settings you set from other places if you tweak it directly. That would be the first thing to check. Make sure you are using the latest printer drivers also.
What OS are you using. I know Mac OS X doesn't like to tell you anything about your printer unless it's connected and powered up. Could be part of the problem if you're on mac... older mac os's and windows don't generally have this issue.
If those things don't help, then I would say maybe nuking the photoshop preferences might be in order. Hold Cmd+Opt+Shift while launching Photoshop and okay the "delete preferences" dialogue. (Ctrl + Alt + Shift on windows).
If nothing else helps, come back with more info and we'll see what goes from there. Good luck.