I have been using Opera on Windows 7 and it seems to be working very well. I'm trying to flip my machine over to uBuntu but I've been having issues with compatibility with the tax program I use. I read where if the internet browser is compatible I shouldn't have a problem. It's just that I want to test before I change. So right now, Opera is my choice for an old machine and outdated OS.
Someone on Yaketys suggested Opera to me, I can't remember who, but thank you!