Win 7 Home Premium 64 Setting up computer, installed Firefox and about a dozen mostly security Add Ons. Everything worked fine (except Text to Voice button would not appear in lower right of FF screen) Was doing more setup, don't know exactly what was in progress when it happened, but all of a sudden all the Add Ons except Avast were gone! Going to reinstall, but would like to avoid that happening again. Computer is for 84 year old cousin who doesn't know much about computers. Thanks!