cant download or install anything on firefox 3.6....Using vista OS....

[C Lou]

I can't download or install anything on the firefox browser and vista OS....I uninstalled it and reinstalled the whole thing and did it "right" this time and everything was the same...preferences and everything.....NOW...I did somehow manage to try to add on an..add-on and when that failed too.... I did a "save as" to my desktop or documents and it installed outside of browser but...it worked for one ADD-on and One persona and now it doesnt work that way anymore..... Ive tried changing what I have in my "Internet options" as far as a location for my downloads and that has not helped.Any other ideas anyone thank you its particularly frustrating b/c Im trying to get a job and cant modify my resume and even save it most of the time...??? Thanks