Since talking about getting rid of ads is a bannable offense in this board, even in PM, I suggest we stick to discussing only the de- and re-installation of IE.
Al Microsoft products are terribly intertwined so that deleting IE will cause you rather a lot of problems. From XP on it's being used not only as a browser but also to view the contents of your own harddrive. If you deinstall it, you will be unable to view the index of your drives, except if you use a DOS emulation. I would strongly advise you not to do it.
You can, however, install a different version over the current one so that you can upgrade as you like and downgrade to the lowest possible version for your OS.
With either, you ought to make a complete backup and a boot CD, just in case.
It might already help a bit if you deinstall a few plugins you don't need.
MS is comperatively tolerant towards browsers from other companies, though, so that you can easily install a second one in addition to IE. Firefox has a few nice basic features and is small. Opera is not bad either. I'd advise not to use Chrome - too much spyware. The damned thing phones home all the time and tells Google your every movement in the net.