Tried Opera once awhile back.. I decided it was a little akward for me to use and I didn't need anymore advertisements on top of all the pop-ups I already get. Now I'm happy with Mozilla and its pop-up blocker
As for the quicklaunch, I'm really not sure. Try to open Moz normally and then close it, see if there is an icon in the taskbar. If so, you just double click on it.
If that doesn't work, installing mozilla over itself shouldn't break anything (or, if you're using 1.3 it might be a good idea to upgrade to 1.4a, I've found it to be stable, hasn't crashed yet)