Deborah,

Try the following:

After closing Firefox, Remove the files in the updates and updates\0 folder: C:\Users\<user>\AppData\Local\Mozilla\Firefox\Mozilla Firefox\updates C:\Program Files\Mozilla Firefox\updates\

(Replacing <user> with your Vista user name.)

See http://kb.mozillazine.org/Software_Update (Software Update not working properly)

If that doesn't work, try downloading the Firefox installer from http://www.getfirefox.com and running it, after exiting Firefox. Your settings won't be lost with this upgrade install.

Thank you rjohnson- I just managed to solve it myself just prior to your post here and am glad you posted because I was wondering where to go to let people know it was now solved.

But again- thanks so much for such a prompt response to my problem- I certainly appreciate it!

Deborah