Hahah... I understand your fear. So from now on if you download any software, please dont delete setup after installing it. Keep the setup saved in your computer for any future use. Ok.
Coming to your question. I say not to both. I suggest you advance to firefox from internet explorer. Firefox is the most coolest browser you can get.
The vast arsenal of firefox addons is simply marvellous.
You can block ads, you can download videos from youtube to your computer. You can remove advertisemnts from yahoo mail and a lot more with firefox.
http://www.getfirefox.com
I am sure you'll like it.
Cheers.
Heheeh and dont forget to save firefox setup on your computer....LOL