Others in this forum were discussing a new update. I can't remember exactly what they said (either the update solved the problem or the update WAS the problem) but you might want to search and see about that.
If you end up having trouble with Office and give up, you might think about giving this a try:
http://www.openoffice.org/. I was having some trouble with Office on Vista and switched after asking about it here. This discussion might be of interest to you:
http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=242x18525I don't know what to tell you about the Firefox issue, other than some offhand mentions I've heard about the new Beta version not working well with Gmail if you check Gmail on the website rather than in Outlook.
Good luck.