I'm going to do a Joudi, and take things bit by bit, Lona.
Some sites you cannot access without adding a plug-in and some sites you just can't access at all.
OK, some sites, such as PC Pals need a Flash plug in. It tells you where to get it, and once you've got it, you won't need to get it again. The only other plug in I can imagine you may require is Java, which you should already have, but if not, again, it's easily downloadable, and you only need to do it once.
There are a small handful of sites which will not work with Mozilla, as the developers of those sites have designed them rigidly for IE. This is not really a fault in Mozilla, but I agree it can be a little inconvenient. All it means is that when you want to access those sites, you have to use IE, but that doesn't stop you using Moz as your default browser.
Another annoying habit Mozilla has.....it has changed all my icons on some of my files with that annoying little red face it has.
This just means that by default, Mozilla will open the file. If you want to change it, just right click the file, select 'Open with...', then 'Choose Program'. You can then select the program you want to open that file with, and if you tick the box, it will open all files of that type with your chosen program in future.
I have tired uninstalling it and it says the uninstall file is missing. Half of it is gone and the other half is in explorer under program files. I was wondering if I should re-install it on top of itself to see if that helps.
If you really want to uninstall the best browser available
and it is saying files are missing, then yes, I would re-install it on top, then uninstall it using Add / Remove Programs. It takes a couple of minutes to uninstall, and sometimes the little box which asks you to confirm you want to remove it gets hidden under other windows, for some reason, which is why you may have disrupted the uninstall process before. If you are going to uninstall it, also delete the Mozilla.org file in C:\Program Files.
I hope the above may be of some use, and may tempt you to give it another chance, Lona!